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TM9100 mobiles

Service Manual

MMA-00017-01
Issue 1
August 2005

Tait Contact Information
Tait Radio Communications
Corporate Head Office
Tait Electronics Ltd
P.O. Box 1645
Christchurch
New Zealand

Technical Support
For assistance with specific technical issues,
contact Technical Support:
E-mail: support@taitworld.com
Website: http://support.taitworld.com

For the address and telephone number of
regional offices, refer to the TaitWorld
website:
Website: http://www.taitworld.com

To our European customers:
Tait Electronics Limited is an environmentally responsible company which
supports waste minimization and material recovery. The European Union’s
Waste Electrical and Electronic Equipment Directive requires that this
product be disposed of separately from the general waste stream when its
service life is over. Please be environmentally responsible and dispose
through the original supplier, your local municipal waste “separate
collection” service, or contact Tait Electronics Limited.

TM9100 Service Manual
© Tait Electronics Limited August 2005

Contents
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Scope of Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Hardware and Software Versions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Enquiries and Comments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Updates of Manual and Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Copyright . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Disclaimer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Associated Documentation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Publication Record . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Alert Notices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Chapter 1 Description of the Radio . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3 Circuit Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Chapter 2 Servicing the Radio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
4 General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
5 Disassembly and Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
6 Servicing Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
7 Power Supply Fault Finding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
8 Interface Fault Finding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
9 Frequency Synthesizer Fault Finding . . . . . . . . . . . . . . . . . . . . . . . . 169
10 Receiver Fault Finding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227
11 Transmitter Fault Finding (50W/40W Radios) . . . . . . . . . . . . . . . . 245
12 Transmitter Fault Finding (25W Radios) . . . . . . . . . . . . . . . . . . . . . 315
13 CODEC and Audio Fault Finding. . . . . . . . . . . . . . . . . . . . . . . . . . 371
14 Fault Finding of Control Head . . . . . . . . . . . . . . . . . . . . . . . . . . . . 397
15 Spare Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 421
Chapter 3 Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .427
16 TMAA02-08 Keypad Microphone . . . . . . . . . . . . . . . . . . . . . . . . . 431
17 TMAA03-02 Security Bracket . . . . . . . . . . . . . . . . . . . . . . . . . . . . 439
18 TMAA04-05 Ignition Sense Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . 443
19 TMAA10-01 Desktop Microphone . . . . . . . . . . . . . . . . . . . . . . . . . 445
20 TMAA10-02 Handset. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 449
21 TMAA10-03 and TMAA10-06 High-Power Remote Speakers . . . . 453
22 TMAA10-04 Remote PTT Kit. . . . . . . . . . . . . . . . . . . . . . . . . . . . 455
23 Installing an Enhanced Remote Kit . . . . . . . . . . . . . . . . . . . . . . . . . 461
24 TOPA-SV-024 Test Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 477

TM9100 Service Manual
© Tait Electronics Limited August 2005

Preface
Scope of Manual
This manual contains information to service technicians for carrying out
level-1 and level-2 repairs of TM9100 radios and accessories.
Level-1 repairs entail the replacement of faulty parts and circuit boards;
level-2 repairs entail the repair of circuit boards, with the exception of
certain special items on the boards. The manual does not cover level-3
repairs, which entail the repair of the special items.

Hardware and Software Versions
This manual describes the following hardware and software versions.
The IPNs (internal part numbers) of the boards are listed below; the last two
digits in the IPN represent the issue of the board.
■

Main board (B1 band) 50W

: 220-01723-02

■

Main board (H5 and H7 bands) 50W/40W : 220-01722-02

■

Main board (B1 band) 25W

: 220-01700-10

■

Main board (H5 and H6 bands) 25W

: 220-01697-10

■

Control-head board

: 220-01718-01

■

Programming application

: version 1.1.0.1

■

Calibration application

: version 1.0.0.0

Enquiries and Comments
If you have any enquiries regarding this manual, or any comments,
suggestions and notifications of errors, please contact Technical Support
(refer to “Tait Contact Information” on page 2).

Updates of Manual and Equipment
In the interests of improving the performance, reliability or servicing of the
equipment, Tait Electronics Ltd reserves the right to update the equipment
or this manual or both without prior notice.

TM9100 Service Manual
© Tait Electronics Limited August 2005

Copyright
All information contained in this manual is the property of
Tait Electronics Ltd. All rights are reserved. This manual may not, in whole
or in part, be copied, photocopied, reproduced, translated, stored, or
reduced to any electronic medium or machine-readable form, without prior
written permission from Tait Electronics Ltd.
All trade names referenced are the service mark, trademark or registered
trademark of the respective manufacturers.

Disclaimer
There are no warranties extended or granted by this manual.
Tait Electronics Ltd accepts no responsibility for damage arising from use of
the information contained in the manual or of the equipment and software
it describes. It is the responsibility of the user to ensure that use of such
information, equipment and software complies with the laws, rules and
regulations of the applicable jurisdictions.

Associated Documentation
The following associated documentation is available for this product:
■

MMA-00009-xx TM9100 Product Safety and Compliance
Information

■

MMA-00007-xx TM9100 User’s Guide

■

MMA-00018-xx TM9100 Installation Guide

■

MMA-00022-xx TM9100 Main Board (H5/H6) 25W
PCB Information

■

MMA-00023-xx TM9100 Main Board (B1) 25W
PCB Information

■

MMA-00024-xx TM9100 Main Board (H5/H6) 50W/40W
PCB Information

■

MMA-00025-xx TM9100 Main Board (B1) 50W PCB Information

■

MMA-00029-xx TM9100 Control-Head Board (Graphical Display)
PCB Information

■

MMA-00026-xx TM9100 PCB Information
(printed, pre-punched and shrink wrapped;
comprises MMA-00022-xx to MMA-00025-xx and
MMA-00029-xx)

The characters xx represent the issue number of the documentation.
All available documentation is provided on the
TM9100/TP9100 Service CD, product code TMAA24-01.
Updates may also be published on the Tait support website.

TM9100 Service Manual
© Tait Electronics Limited August 2005

Publication Record
Issue
01

Publication Date
August 2005

Description
first release

Alert Notices
Within this manual, four types of alerts are given to the reader: warning,
caution, important and note. The following paragraphs illustrate each type
of alert and its associated symbol.

Warning!!

This alert is used when there is a potential risk
of death or serious injury.

Caution

This alert is used when there is the risk of minor or
moderate injury to people.

Important

This alert is used to warn about the risk of equipment damage or malfunction.

Note

This alert is used to highlight information that is required to
ensure that procedures are performed correctly.

Abbreviations
Abbreviation

Description

ACP

Adjacent Channel Power

ADC

Analog-to-Digital Converter

AGC

Automatic Gain Control

ALC

Automatic Level Control

APCO

Association of Public Safety Communications Officials

ASC

Accredited Service Center

BOM

Bill of Materials

C4FM

Compatible Four-level Frequency Modulation

CCTM

Computer-controlled Test Mode

CODEC

Coder-Decoder

TM9100 Service Manual
© Tait Electronics Limited August 2005

Abbreviation

Description

CSO

Customer Service Organisation

CTCSS

Continuous-tone-controlled Subaudible Signaling

DAC

Digital-to-Analog Converter

Direct Current

DSP

Digital Signal Processor

DTMF

Dual-Tone Multi-Frequency

EPTT

External PTT (Press-To-Talk)

ESD

Electrostatic Discharge

FCL

Frequency Control Loop

Front-End

FEC

Forward Error Correction

FPGA

Field-Programmable Gate Array

GPIO

General Purpose Input/Output

GPS

Global Positioning System

GUI

Graphical User Interface

Integrated Circuit

IPN

Internal Part Number

Intermediate Frequency

In-Phase and Quadrature

ISC

International Service Center

LCD

Liquid-Crystal Display

LED

Light-Emitting Diode

LNA

Low-Noise Amplifier

Local Oscillator

LPF

Low-Pass Filter

NPN

Negative-Positive-Negative

P25

Project 25

Power Amplifier

PCB

Printed Circuit Board

PLL

Phase-Locked Loop

PNP

Positive-Negative-Positive

TM9100 Service Manual
© Tait Electronics Limited August 2005

Abbreviation

Description

PSU

Power Supply Unit

PTT

Press-To-Talk

RISC

Reduced Instruction Set Computing

RSSI

Received Signal Strength Indication

SFE

Software Feature Enabler

SMA

Sub Miniature Version A

SMD

Surface-Mount Device

SMT

Surface-Mount Technology

SMPS

Switch-Mode Power Supply

SPI

Serial Peripheral Interface

TCXO

Temperature-compensated Crystal Oscillator

TEL

Tait Electronics Limited

VCO

Voltage-Controlled Oscillator

VCXO

Voltage-Controlled Crystal Oscillator

TM9100 Service Manual
© Tait Electronics Limited August 2005

TM9100mobiles

Chapter 1
Description of the Radio

TM9100 Service Manual
© Tait Electronics Limited August 2005

Chapter 1 – Contents
1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
1.1 Frequency Bands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
1.2 RF Output Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
1.3 Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
1.4 Product Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
1.5 Labels. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
1.6 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2.1 Mechanical Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2.3 Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
2.4 Hardware and Software Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
2.5 Operation in Receive Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
2.6 Operation in Transmit Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Circuit Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
3.1 Transmitter Circuitry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
3.2 Receiver Circuitry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
3.3 Frequency Synthesizer Circuitry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
3.4 Frequency Control Loop. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
3.5 CODEC and Audio Circuitry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
3.6 Power Supply Circuitry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
3.7 Interface Circuitry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
3.8 Digital Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
3.9 Control-Head Board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

TM9100 Service Manual
© Tait Electronics Limited August 2005

Introduction
The TM9100 series is a range of high-performance microprocessorcontrolled radios for digital (APCO project 25-compatible), analog and
mixed operation for voice and data communication. The radios are designed
for installation in vehicles but can also be used in desktop, remotemonitoring and similar applications.
This manual includes the information required for servicing the radio and
its accessories.
Figure 1.1

TM9155 mobile radio

This section describes the different options available for:
■

frequency bands

■

RF output power

■

accessories

■

product codes

TM9100 Service Manual
© Tait Electronics Limited August 2005

Introduction

This section also gives an overview of the labels on the product and the
specifications.

1.1

Frequency Bands
The radios are available in the following frequency bands:
■

136 to 174MHz (B1)

■

400 to 470MHz (H5)

■

450 to 530MHz (H6)

■

450 to 510MHz (H7)

The frequency bands are implemented by different main boards in the radio
body. The control heads are identical for all frequency bands.

1.2

RF Output Power
The radio bodies are available with 50W/40W and 25W RF output power.
The two RF output power options are implemented by different main
boards in the radio body, mechanically different radio bodies, and different
power connectors. The control heads are identical for all RF output power
options.
The 50W/40W radio is available in the following frequency bands:
■

B1 (50W)

■

H5 (40W)

■

H7 (40W)

The 25W radio is available in the following frequency bands:

Introduction

■

TM9100 Service Manual
© Tait Electronics Limited August 2005

1.3

Accessories
Tait offers a large variety of audio accessories, installation kits, internal
options boards and other accessories such as a desktop power supply.
For more information on these accessories refer to “Chapter 3 Accessories”
on page 427.

Audio Accessories

Installation Kits

The radios allow for the connection of a comprehensive range of audio
accessories:
■

rugged microphone (standard)

■

keypad microphone

■

handset

■

high-power remote speaker

■

remote PTT kit

The radio is delivered with a vehicle installation kit with U-cradle.
Installation of the radio is described in the installation guide.
Optional installation kits are:
■

remote control-head kit for remote installation of the control head

■

security bracket for secure and quick-release installation

Internal Options
Boards

The radio provides space for an internal options board inside the radio body
connecting to an internal options connector. An aperture for an external
options connector is also provided.

Desktop Power
Supply

A desktop power supply including the parts for mounting the radio is
available for desktop installations.

TM9100 Service Manual
© Tait Electronics Limited August 2005

Introduction

1.4

Product Codes
This section describes the product codes used to identify products of the
TM9100 mobile radio product line.

General

The product codes of the TM9100 mobile radio product line have the
format:
TMAabc–ddee
where:

Radio Bodies

■

a identifies the product category:
A=accessory, B=radio body, C=control head, S=software feature

■

b, c, dd and ee identify specific product features.

The product codes of the radio bodies have the format:
TMAB3c–ddee
where:

Control Head

■

3 identifies the architecture of the digital board:
3=APCO digital
1 and 2 identify the digital boards of the analog TM8000 product line.

■

c identifies the RF output power:
2=25W, 4=30 to 59W, 5=30 to 59W (trigger-base)

■

dd identifies the frequency band:
B1=136 to 174MHz, H5=400 to 470MHz, H6=450 to 530MHz,
H7=450 to 520MHz
Other characters identify frequency bands of the analog TM8000
product line.

■

ee identifies any radio options:
00=BNC RF connector, 01=mini-UHF RF connector

The product code of the control head has the format:
TMAC41–dd
where:

Introduction

■

4 identifies the control-head type (4=graphical-display control head)
Other numbers identify control heads of the analog TM8000 product
line.

■

1 identifies the control-head configuration (1=APCO digital)
0 identifies the control-head configuration of the analog TM8000
product line.

■

dd identifies label and branding options.

TM9100 Service Manual
© Tait Electronics Limited August 2005

1.5

Labels
Four external labels are attached to the bottom of the radio body:
■

compliance information

■

serial number and product code

■

hot surface safety warning

■

RF exposure safety warning

TM9100 Service Manual
© Tait Electronics Limited August 2005

TMAH6C

TAIT

Made in
New Zealand

Figure 1.2

Labels of the TM9100 product line

N46

IC: 737A-TMAH6C
FCC ID: CASTMAH6C
Contains intellectual property licenced
by Digital Voice Systems Inc, Motorola
Inc and Tait Electronics Ltd.
Details in user documentation.

S/N 19061964
TMAB32-H600
450-530 MHz

Tait Electronics Ltd, NZ

Introduction

1.6

Specifications
Table 1.1 shows the specifications for the TM9100 radios. The parameter
values quoted are minimum values. These specifications are valid for the date
of publication only. For up-to-date specifications, refer to the area on the
TaitWorld website reserved for TM9100 products.

Introduction

Table 1.1

Specifications

Parameter

Values

Basic characteristics

50W/40W radio:

Frequency ranges:
• B1 band
• H5 band
• H6 band
• H7 band

136 to 174MHz
400 to 470MHz
not available
450 to 520MHz

Channel spacing:
• B1 band
• H5, H6, H7 bands

12.5kHz/25kHz/30kHz
12.5kHz/25kHz

Channels/talkgroups (simplex or semi-duplex)

512

Frequency stability

±1.5ppm

Zones

Supply current:
• receive mode
•

squelched
full audio

transmit mode

RF connector
Power connector:
• Power supply
• External speaker

Interface connectors:
• microphone connector
• auxiliary connector
• internal options connector
Physical characteristics

100mA
500mA
<10A

25W radio:

136 to 174MHz
400 to 470MHz
450 to 530MHz
not available

110mA
525mA
<5.5A

50Ω miniature UHF or BNC (optional)

between 10.8 and 16 V DC
maximum power 10 W into 4 Ω
balanced load configuration
Ports:
1 serial, 1 I/O
1 serial, 3 input, 4 I/O, 1 audio tap in, 1 audio tap out
1 serial, 7 I/O, 1 audio tap in, 1 audio tap out
50W/40W radio:

25W radio:

Weight

55.87 oz. (1.60kg)

49.47 oz. (1.40kg)

Dimensions:
• length
• width
• height

8.43 in. (214mm)
7.09 in. (180mm)
2.68 in. (68mm)

7.64 in. (194mm)
7.09 in. (180mm)
2.68 in. (68mm)

Introduction

TM9100 Service Manual
© Tait Electronics Limited August 2005

Table 1.1

Specifications (continued)

Parameter

Values

Environmental conditions
Operating temperatures
Standards
• IP54

• MIL-STD 810C, D, E and F
(for details contact Technical Support)

−22°F to +140°F (−30°C to +60°C)

Meets the requirements for sealing against:
• dust
• rain
Meets the requirements regarding the following aspects:
• low pressure
• high temperature
• low temperature
• temperature shock
• solar radiation
• rain
• humidity
• salt fog
• dust
• vibration
• shock

Receiver
Analog sensitivity (12dB SINAD)

<0.25µV (−119dBm)

Digital sensitivity (TIA/EIA) 5% BER#

< 0.20µV (−121dBm)

Intermodulation rejection

>–75dB

Adjacent channel selectivity:
• 20kHz/30kHz channel
• 12.5kHz channel

>–75dB
>–65dB

Spurious responses rejection

>–75dB

FM hum and noise:
• 20kHz/30kHz channel
• 12.5kHz channel

>–43dB
>–40dB

Audio distortion at rated audio

<3%

Audio bandwidth

300Hz to3 kHz (flat or with de-emphasis)

Receive detect time
(From the time an RF signal is first present at the
antenna to the time when the BUSY DETECT line
changes state)

< 3ms

TM9100 Service Manual
© Tait Electronics Limited August 2005

Introduction

Table 1.1

Specifications (continued)

Parameter

Values

Transmitter

50W/40W radio:

25W radio:

Output power:
• level 1 (very low)
• level 2 (low)
• level 3 (medium)
• level 4 (high)

10W
15W
25W (VHF), 20W (UHF)
50W (VHF), 40W (UHF)

Modulation limiting:
• 25kHz/30kHz channel
• 12.5kHz channel

<±5kHz
<±2.5kHz

FM hum and noise:
• 25kHz/30kHz channel
• 12.5kHz channel

>– 41dB
>– 37dB

1W
5W
12W
25W

Conducted and radiated emissions:
• up to 1GHz
<−36dBm
< −30dBm
• between 1 and 4GHz
(for radio operating frequencies below 500 MHz)
< −30dBm
• between 1 and 12.75GHz
(for radio operating frequencies above 500MHz)
Audio bandwidth

300Hz to 3kHz (flat or with pre-emphasis)

Audio response

+1/–3dB

Audio distortion

<3% at 1kHz 60% modulation

Transmit rise time
(from the time the external PTT line is asserted to
the time when the RF output power reaches 90%
of its final value)

<10ms

Introduction

TM9100 Service Manual
© Tait Electronics Limited August 2005

Table 1.2

Typical current consumptions by radio while not transmitting (analog mode) and by
control head

Parameter

Value

Radio not operating:
• radio off (no links fitted)
2.2mA
• radio off (links LK1, LK2, LK3 fitted)
3.3mA
(using ignition control to switch radio on and off)
• radio on stand-by (links LK1, LK2, LK3 fitted)
52mA
(using ON/OFF key on control head to switch radio on and off)
Receiver:
• receiver idle (not scanning)
• receiver active, mute on
• receiver active, 3W audio into 16Ω
• receiver active, 10W audio into 4Ω

104mA
158mA
585mA
1.6A

Current consumptions by control head only:
• no back-lighting, no LEDs
• maximum back-lighting, no LEDs
• maximum back-lighting and LEDs on
• additional current with LCD heating on

13.3mA
99.9mA
102mA
220mA

Table 1.3

Typical current consumptions by radio body while transmitting (analog mode)
Values at different power levels

Parameter
Very low Low

Medium

High

40W/50W radio:
• B1 band
• H5 band
• H7 band

4.0A
3.6A
3.5A

4.8A
4.4A
4.3A

6.0A
5.1A
5.0A

9.0A
7.6A
7.6A

25W radio:
• B1 band
• H5 band
• H6 band

1.1A
1.2
1.2A

2.0A
2.3A
2.3A

2.9A
3.3A
3.4A

4.4A
5.1A
5.2A

TM9100 Service Manual
© Tait Electronics Limited August 2005

Introduction

TM9100 Service Manual
© Tait Electronics Limited August 2005

Description
This section describes the mechanical design and architecture of the radio,
explains the operation of the transceiver and the control head, and gives
pinouts of the radio connectors.

2.1
Overview

Mechanical Design
The radio consists of the following main components:
■

control head B

■

radio body C

Figure 2.1

Components of the radio

D
E

3068z_01

The control head B clips firmly to the front face of the radio body C,
where a seal E provides IP54 class protection. A control-head loom D
connects the control head to the radio body. Two dot-dash-dot marks at the
bottom of the radio body indicate the positions where a screwdriver is
applied to separate the control head from the radio body.

TM9100 Service Manual
© Tait Electronics Limited August 2005

Description

2.1.1

Radio Body

Overview

The radio body consists of the following main components (see Figure 2.2
on page 25):
■

cover B

■

lid D

■

internal options board (optional)

■

chassis G

■

main-board assembly F

Cover

The black plastic cover B wraps over the top and sides of the radio body.
Apertures in the sides of the cover allow access to the four external screw
bosses of the radio body used for mounting the radio to the U-bracket.

Lid

The aluminum lid D is attached to the chassis G with four M4x16 Torxhead screws C. A seal fitted inside a groove at the underside of the lid
provides for IP54 class protection. The rear of the lid has an aperture for an
external options connector, which may be fitted if an internal options board
is used. If no external options connector is used, the aperture is sealed with
a bung for IP54 class protection. The lid contains two of the four screw
bosses to attach the radio to the U-bracket of the installation kit.

Internal Options
Board (Optional)

On the inside of the lid, nine screw points are provided for mounting an
internal options board, which can be sized and shaped as required.
The internal options board connects to the internal options connector of
the main board. Tait offers a range of internal options board, which are
described in the accessories section of this manual. For more information on
how to create your own internal options board, contact Tait Electronics
Limited.

Chassis

The aluminum chassis g is the different for the 50W/40W radio and the
25W radio.
The chassis G houses the main-board assembly F, which is attached with
five screws E to screw bosses inside the chassis and with two screws I
through the rear of the chassis to the heat-transfer block.
The rear of the chassis has apertures for the RF, power and auxiliary
connectors of the main board. If the auxiliary connector is not used, the
aperture is sealed with a rubber bung J for IP54 class protection.
The RF connector has a rubber seal H which is fitted inside the aperture
for the RF connector.

Description

TM9100 Service Manual
© Tait Electronics Limited August 2005

Figure 2.2

Components of the radio body

Cx4
D

Ex5
F

1)
thermal
paste

G
H
Ix2

J
3630z_01

B
C
D
E
F

cover
screw M4x16 (x4)
lid assembly
screw M3x10 (x5)
main-board assembly

TM9100 Service Manual
© Tait Electronics Limited August 2005

G
H
I
J
1)

chassis
auxiliary connector bung
screws M4x16 (x2)
seal
gap pad (50W/40W radio only)

Description

The front of the chassis has an aperture for the control-head connector.
The control-head seal is fitted inside a groove around the flange at the front
face of the chassis and provides for IP54 class protection when the control
head is fitted. Two dot-dash-dot marks at the underside side of the chassis
indicate the leverage points for removing the control head from the radio
body.
The sides of the chassis contain two of the four screw bosses to attach the
radio to the U-bracket of the installation kit.
For heat dissipation, the chassis has heat fins at the rear, grooves at the
bottom, and holes in the front.
The heat fins at the rear of the 50W/40W radio are longer than those of the
25W radio. The grooves at the bottom of the 50W/40W radio are deeper
than those of the 25W radio.
For additional heat dissipation, the 50W/40W radio has an additional
L-shaped gap pad 1) between the chassis and the main board.

Description

TM9100 Service Manual
© Tait Electronics Limited August 2005

Main-Board
Assembly

The main-board assembly consists of the following components
(see Figure 2.3):
■

■
■

main board 1^ with SMT components, digital board D, shielding cans,
and connectors
heat-transfer block H
mounting and sealing elements for the connectors at the rear of the radio
body

Figure 2.3

Components of the main-board assembly

Cx2
E

Bx3

D
1&

F
G
H
I
1!

1^
1%

thermal
paste

1#
B
C

M3x10 screw (x3)
50W/40W radios:
M2.2x10 PT screw (x2)
25W radios:
K30x8 PT screw (x2)

D
E
F
G
H
I

digital board
internal options connector
auxiliary connector
inner foam D-range seal
heat-transfer block

1$
3631z_01

J
1)
1!
1@
1#
1$
1%
1^
1&

D-range screwlock fastener (x2)
power connector seal
power connector
gap pad (50W/40W radio only)
hexagonal nut
lock washer
RF connector
main board
control-head connector

outer foam seal

TM9100 Service Manual
© Tait Electronics Limited August 2005

Description

The main board 1^ is attached to the heat-transfer block H with three
M3x10 Torx-head screws B and the fastening elements J, 1# and 1$ of the
auxiliary and RF connectors.
The inner foam D-range seal G seals the auxiliary connector against the
heat-transfer block. The power connector seal 1) seals the power connector
against the heat-transfer block.
The power connector seal 1) of the 50W/40W radio (blue) is different to
the seal of the 25W radio (black).
Main Board

The main board 1^ is a printed circuit board in SMT design with
components on the top and bottom sides. A digital board D is reflowsoldered to the main board. Most components are shielded by metal cans.
There are different main boards for each frequency band and each RF
output power configuration.
The internal options connector E for connecting an internal options board
and the factory connector (not illustrated) for factory use are soldered to the
top side of the main board. The control-head connector 1& (facing the front
of the radio) and the auxiliary F, power 1! and RF 1% connectors (facing
the rear of the radio) are located on the bottom side of the main board.
The 50W/40W radio has a black power connector 1! and the 25W radio
has a white power connector.
For more information on the connectors, refer to “Connectors” on
page 34.
For heat dissipation, one of the screw bosses inside the chassis is in contact
with the underside of the main board. A larger copper plate at the underside
of the main board connects to the body of the heat-transfer block.
The 50W/40W radio has an additional gap pad between the heat-transfer
block and the main board 1^ which connects to an additional copper plate
at the bottom side of the main board.

Heat-Transfer Block

The aluminum heat-transfer block H dissipates heat from the main board to
the heat fins of the chassis. The heat-transfer block has a contact surface to
the larger copper plate at the underside of the main board 1^, and a contact
surface to the rear of the chassis. All contact surfaces are coated with thermal
paste.
Two self-adhesive foam seals G and I around the aperture of the auxiliary
connector on either side of the heat-transfer block and the power connector
seal 1) inside the aperture of the power connector are fitted to the heattransfer block.

Description

TM9100 Service Manual
© Tait Electronics Limited August 2005

2.1.2

Control Head

Overview

The control head can be divided into the following main areas:
■

front panel with control elements, indicators, LCD, speaker, and
concealed microphone

■

space-frame and seals

■

control-head board with SMT components, shielding cans, connectors,
and volume potentiometer

■

control-head loom with female-female adapter

■

adapter flange

The circled numbers in this section refer to the items in Figure 2.4 on
page 31.
Front Panel
Assembly

The front panel assembly 1^ consists of an injection-moulded plastic part
with an integrated transparent light pipe element for the radio STATUS LEDs,
a transparent lens which cannot be replaced, a cloth membrane which is
fixed to the speaker grille, and a foam seal inside a rectangular LCD recess
behind the lens. A label 1* with the radio model number is attached to the
front panel assembly with self-adhesive coating and can be replaced for
rebranding purposes.
Three clips on the rear side of the front panel assembly snap onto the spaceframe to hold the keypads 1# and 1#, the LCD assembly 1@ and the speaker
1! in place. The rear side of the front panel assembly also has four screw
bosses to fasten the control-head board F.

Knob for
Volume-Control
Potentiometer

The knob for the volume-control potentiometer 1& is fitted to the shaft of
the volume-control potentiometer, which is soldered to the control-head
board F.

Keypads

The main keypad 1# (for the function, selection, and scroll keys) and the
power keypad 1$ protrude through apertures in the front panel assembly 1^.
The rear sides of these keypads connect directly to the relevant contacts on
the control-head board F.

LCD Assembly

The graphical-display LCD assembly 1@ sits on a foam seal inside a
rectangular recess of the front panel assembly 1^. Another foam seal is
attached to the rear of the LCD with self-adhesive coating. The LCD
assembly has a loom, which runs through a slot in the space-frame J and
connects to a connector on the rear side of the control-head board F.

TM9100 Service Manual
© Tait Electronics Limited August 2005

Description

Speaker

The speaker 1! sits inside a round recess of the front panel assembly, where
a cloth membrane is fixed to the speaker grille. The speaker clamp 1) holds
the speaker in position. The speaker cable plugs into the speaker connector
on the rear side of the control-head board F.
Note

In some configurations the speaker may be disconnected.

Concealed
Microphone

A concealed microphone 1% consisting of the microphone capsule and a
rubber seal is fitted in a round recess inside the front panel assembly 1^.
The microphone leads are soldered to two pads on the top side of the
control-head board.

Space-Frame

The aluminum space-frame J snaps into the three clips of the front panel
assembly 1^. The front side of the space-frame holds the keypads, the LCD
assembly, and the speaker in place and at the same time allows access to their
electrical contacts. The rear side of the space-frame has four through-holes
for the screws E of the control-head board F and two screw bosses to fit
the adapter flange C. Two light pipes H and I are fitted in recesses in the
space-frame and direct light from LEDs on the control-head board to the
front panel. A slot at the top edge of the space-frame allows the loom of the
LCD assembly 1@ to run to the control-head board.

Seals

Two identical ring seals G fitted to grooves around the perimeter of the
space-frame provide for IP54 class protection.

Description

TM9100 Service Manual
© Tait Electronics Limited August 2005

Figure 2.4

Components of the control head

Bx2
C

D
Ex4

H
I

B
C

M4 x 12 Taptite screw (x2)

control-head loom assembly with
female-female adapter

E
F
G
H
I
J
1)
1!
1@
1#
1$
1%
1^
1&

3 x 10 PT screw (x4)

adapter flange

control-head board
space-frame seal (x2)
short light pipe
long light pipe
space-frame
speaker clamp
speaker
LCD assembly
main keypad
power keypad
concealed microphone
front panel assembly
knob for volume-control potentiometer

1%
1#
1$

3451z_02

TM9100 Service Manual
© Tait Electronics Limited August 2005

Description

Control-Head Board

The control-head board F is a printed circuit board in SMT design with
components on the top and bottom sides. Some SMT components are
shielded by metal cans.
The control-head board is fitted to the front panel assembly 1^ through the
space-frame J with four 3x10 PT screws E.
The side facing the radio body has the connectors for the connection of the
control-head loom, the LCD loom, the speaker, an optional control-head
options board, and pads for the leads of the concealed microphone.
Figure 2.5

Connectors of the control-head board

pads for leads of
concealed microphone

connector for speaker

connector for
loom of LCD assembly

connector for control-head
options board

connector for
control-head loom

The side facing the front panel has the volume-control potentiometer, the
microphone connector, the indicator and backlight LEDS, and the contacts
for the keypads.
Control-Head Loom

The control-head loom D connects the connector on the control-head
board to the control-head connector of the radio body. For more
information refer to “Control-Head Connectors” on page 40.

Adapter Flange

The adapter flange C is an injection-moulded plastic part, which is fitted to
the space-frame with two M4x12 Taptite screws B.

Description

TM9100 Service Manual
© Tait Electronics Limited August 2005

2.2

User Interface
Figure 2.6 shows the controls and indicators of the user interface. For more
information refer to the TM9100 User’s Guide.
Some keys have functions assigned to both short and long key presses.
A short key press is less than one second, and a long key press is more than
one second.
Figure 2.6

User interface

press-to-talk
(PTT) key
radio status LEDs

microphone

green
red amber
speaker

display
on/off key
volume
control

microphone
socket

function keys
1 to 4

TM9100 Service Manual
© Tait Electronics Limited August 2005

scroll keys
left
selection key

right
selection key

Description

2.3

Connectors
This section describes the specifications and pinouts of the connectors of the
radio body and the control head.

Overview

Figure 2.7 provides an overview of the connectors:
Figure 2.7

Connectors

Volume
Control

Control-Head
Options Connector
RF Connector

Microphone
Connector

Control-Head
Options Board

Control-Head
Loom
Keys

Control-Head
Connector

Control-Head
Board

Main Board

Internal
Options
Connector

Power
Connector

LCD

LEDs

Internal
Options
Loom

Pads for
Concealed
Microphone
Speaker
Connector
Factory
Connector
(Factory Only)

Speaker

Auxiliary
Connector

Internal
Options
Board

External
Options
Connector

Speaker
Leads

Figure 2.8 shows the connectors of the radio body.
Figure 2.9 shows the connectors of the control head.
For information on the factory connector of the main board and the internal
connectors of the control head, refer to the PCB information of the main
boards and the control-head board.

Description

TM9100 Service Manual
© Tait Electronics Limited August 2005

Figure 2.8

Connectors of the radio body (25W radio)

front view
control-head
connector
provision for
external options
connector

provision for
additional
connector

rear view
auxiliary
connector

power
connector

RF
connector
internal options
connector

top view

TM9100 Service Manual
© Tait Electronics Limited August 2005

Description

Figure 2.9

Connectors of the control head

front view
microphone
connector

control-head
connector

rear view without adapter flange

2.3.1

RF Connector
The RF connector is the primary RF interface to the antenna. The RF
connector is a standard mini-UHF connector or a BNC connector with an
impedance of 50Ω.
Important

Table 2.1

RF connector - pins and signals

Pinout

Signal Name

Signal Type

RF analog

GND

RF ground

rear view

The maximum RF input level is +27dBm. Higher levels
may damage the radio.

Description

TM9100 Service Manual
© Tait Electronics Limited August 2005

2.3.2

Power Connector
The power connector is the interface for the primary 13.8V power source
and the external speaker. The primary power source can be the vehicle
battery or a mains-fed DC power supply. There are different power
connectors for the 50W/40W and 25W radios.
Important

Table 2.2

The speaker load configuration is balanced; the speaker
output lines must not be connected to ground. Connecting
a speaker output line to ground will cause audio power
amplifier shutdown

Power connector (radio) – pins and signals

Pinout

Signal name
AGND

Earth return for radio body power
source.

Ground

SPK–

External speaker output. Balanced load
configuration.

Analog

SPK+

External speaker output. Balanced load
configuration.

Analog

13V8_BATT

DC power input for radio body and
control head.

Power

25W radio
1

Signal type

50W/40W radio

rear view

Description

rear view

TM9100 Service Manual
© Tait Electronics Limited August 2005

Description

2.3.3

Auxiliary Connector
The auxiliary connector is the standard interface for external devices that are
typically connected to a radio. The auxiliary connector is a 15-way
standard-density D-range socket. The auxiliary connector provides a serial
port, three programmable input lines, four programmable digital I/O lines
and audio I/O.
The I/O lines can be programmed for a variety of functions, logic levels,
and in some cases, direction. Audio lines can also be programmed to tap
into, or out of, different points in the audio processing chain. For more
information refer to the online help of the programming application.

Table 2.3

Auxiliary connector – pins and signals

Pinout

B
C
D
E
F
G
H
I

J
1)
1!
1@
1#
1$
1%

rear view

Signal name

Description

Signal type

AUX_GPI1

General purpose digital input.
Programmable function.

Digital, 3V3 CMOS

AUX_GPI2

General purpose digital input.
Programmable function.
With LK3 fitted, GPI2 is an
emergency power sense input.a

Digital, 3V3 CMOS

AUX_GPI3

General purpose digital input.
Programmable function.
With LK2 fitted, GPI3 is a power
sense input.a

Digital, 3V3 CMOS

AUX_GPIO4

AUX_GPIO5

AUX_GPIO6

Programmable function and
direction.
Pads available to fit a higher power
driver transistor on GPIO4 line

Digital, 3V3 CMOS
input; open collector
output with pullup

AUX_GPIO7

AUX_TXD

Asynchronous serial port Transmit data

Digital, 3V3 CMOS

AUX_RXD

Asynchronous serial port Receive data

Digital, 3V3 CMOS

AUD_TAP_IN

Programmable tap point into the Rx
or Tx audio chain. DC-coupled.

Analog

AUD_TAP_OUT

Programmable tap point out of the
Rx or Tx audio chain. DC-coupled.

Analog

AUX_MIC_AUD Auxiliary microphone input.
Electret microphone biasing
provided. Dynamic microphones are
not supported.

Analog

RSSI

Analog RSSI output.

Analog

Switched 13.8V supply. Supply is
switched off when radio body is
switched off.

Power

Analog ground

Ground

+13V8_SW

AGND

a. For more information on hardware links refer to“Power-Sense Options” on page 82.
b. Can be switched or unswitched. For more information refer to “Connector Power Supply Options” on page 85.

Description

TM9100 Service Manual
© Tait Electronics Limited August 2005

2.3.4

Internal Options Connector
When installing an internal options board, the internal options connector is
the electrical interface to the main board of the radio body.
The internal options connector provides similar I/O to the auxiliary
connector. The internal options connector is an 18-pin 0.1 inch pitch
Micro-MaTch connector.
Important

Table 2.4

The digital I/O signals are intended to interface directly
with compatible logic signals only. Do not connect these
signals to external devices without appropriate signal conditioning and ESD protection.

Internal options connector – pins and signals

Pinout

CB
ED
GF
IH
1)J
1@1!
1$1#
1^1%
1*1&
top view

Signal

Description

Signal type

13V8_SWa

Switched 13V8 supply. Supply is switched Power
off when the Radio Body is switched off.

AUD_TAP_OUT

Programmable tap point out of the Rx or
Tx audio chain. DC-coupled.

Analog

AGND

Analog ground.

Ground

AUX_MIC_AUD Auxiliary microphone input.
Analog
Electret microphone biasing provided.
Dynamic microphones are not supported.

RX_BEEP_IN

Receive sidetone input. AC-coupled.

AUD_TAP_IN

Programmable tap point into the Rx or Tx Analog
audio chain. DC-coupled.

RX_AUD

Receive audio output. Post volume
control. AC-coupled.

Analog

RSSI

Analog RSSI output.

Analog

9…15 IOP_GPIO1…7

Analog

Digital.
General-purpose port for input and
3V3 CMOS
output of data. Programmable function
and direction. With LK4 fitted, GPIO7 is a
power sense inputb.

DGND

Digital ground.

Ground

IOP_RXD

Asynchronous serial port - Receive data.

Digital.
3V3 CMOS

IOP_TXD

Asynchronous serial port - Transmit data.

Digital.
3V3 CMOS

a. Can be switched or unswitched. For more information refer to “Connector Power Supply Options” on page 85.
b. For more information on hardware links refer to“Power-Sense Options” on page 82.

2.3.5

Provision for External Options Connector
The radio has a mechanical interface for the external connector of an
internal options board. This external options connector can be a 9-way
standard-density or 15-way high-density D-range connector. If no internal
options board is installed (standard configuration), the hole for the external
options connector is sealed by a bung.

TM9100 Service Manual
© Tait Electronics Limited August 2005

Description

2.3.6

Control-Head Connectors
The control-head loom connects the connector on the front of the radio
body to the connector on the rear of the control head.
The connector on the front of the radio body is an 18-way two-row rightangled IDC (insulation displacement connector) SMD header socket.
The connector on the rear of the control head is an 18-way 0.1 inch pitch
Micro-MaTch SMD socket.

Table 2.5

Control-head connectors – pins and signals

Pinout

Signal

RX_AUD

Analog

CEGI1)1@1$1^1*
BDFHJ1!1#1%1&

Receive audio output. Post volume
control. AC-coupled.

+13V8a

Power

front view
of radio body

Power supply output from radio body
power source.

CH_TXD

Asynchronous serial port Transmit data.

Digital. 3V3 CMOS.

CH_PTT

PTT input from microphone.
Also carries the hookswitch signal.

Digital

CH_MIC_AUD Fist microphone audio input.

Analog

AGND

Analog ground.

Ground

CH_RXD

Asynchronous serial port - Receive data. Digital. 3V3 CMOS.

DGND

Digital ground.

Ground

CH_ON_OFF

Hardware power on/softwarecontrolled power off input. Active low.

Digital

VOL_WIP_DC

DC signal from volume pot wiper
(not used, connected to AGND).

Analog

CH_SPI_DO

Data output signal to control head.

Digital. 3V3 CMOS.

CH_LE

Latch enable output to control head.

Digital. 3V3 CMOS.

CH_GPIO1

General purpose digital input/output.

Digital. 3V3 CMOS
input.
Open collector
output with pullup.

+3V3

Power supply to control head digital
circuits.

Power

CH_SPI_DI

Data input from control head.

Digital. 3V3 CMOS.

CH_SPI_CLK

Clock output to control head.

Digital. 3V3 CMOS.

SPK–

Speaker audio output for non-remote
control head. Balanced load
configuration.

Analog

SPK+

Speaker audio output for non-remote
control head. Balanced load
configuration.

Analog

CB
ED
GF
IH
1)J
1@1!
1$1#
1^1%
1*1&
top view of
control-head
board

Description

Signal type

a. Can be switched or unswitched. For more information refer to “Connector Power Supply Options” on page 85.

Description

TM9100 Service Manual
© Tait Electronics Limited August 2005

2.3.7

Microphone Connector
The microphone connector of the control head is an RJ45 socket.
When the control head is connected to the control-head connector of the
radio body using the loom provided, the microphone connector uses the
following eight control-head connector signals:

Table 2.6

Microphone connector – pins and signals

Pinout

front view

Signal name

Description

Signal type

MIC_RX_AUD Receive audio output.

Analog

+13V8a

Power supply output. Switched off
when radio body is switched off.

Power

MIC_TXD

Asynchronous serial port Transmit data.

3.3V CMOS

MIC_PTT

PTT input from microphone. Also carries Digital
hookswitch signal.

MIC_AUD

Fist microphone audio input.

Analog

AGND

Analog ground.

Analog ground

MIC_RXD

Asynchronous serial port - Receive data. 3.3V CMOS

MIC_GPIO1

General purpose digital input/output.

Open collector out
3.3V CMOS in

a. Can be switched or unswitched. For more information refer to “Connector Power Supply Options” on page 85.

TM9100 Service Manual
© Tait Electronics Limited August 2005

Description

2.4

Hardware and Software Architecture
This section describes the hardware and software modules of the radio and
their interaction in the functioning of the radio.

Overview

2.4.1

Hardware Architecture
The electrical hardware of the radio is implemented on a main board inside
the radio body and a control-head board inside the control head.
For a detailed description and block diagrams of individual circuits, refer to
“Circuit Descriptions” on page 23.

Main Board

The main board inside the radio body includes the following circuitry:
■

transmitter

■

receiver

■

frequency synthesizer

■

digital board with a RISC processor and custom logic (implemented on
an FPGA), memory, and a DSP

■

CODEC and audio

■

interface

■

power supply

The main board has an internal options connector which allows internal
options boards to access a variety of discrete and programmable signals.
For more information refer to “Internal Options Connector” on page 39.
For a basic block diagram of the main board, refer to Figure 2.10 on
page 43.
For a more detailed block diagram of the transceiver, refer to Figure 2.12 on
page 48 (analog mode) and Figure 2.13 on page 49 (digital mode).
Control-Head Board

The control-head board includes:
■

the circuitry needed for the controls and indicators on the front panel

■

with a RISC processor and custom logic (implemented on an FPGA),
and memory

For a block diagram of this control-head board, refer to Figure 3.11 on
page 91.
The control head has a concealed microphone inside the control head and
also has a provision for a separate circuit board that may be designed to
perform a variety of tasks including—but not limited to—Bluetooth
connectivity. No separate circuit board is required for a dynamic
microphone.

Description

TM9100 Service Manual
© Tait Electronics Limited August 2005

RF Connector

TM9100 Service Manual
© Tait Electronics Limited August 2005
Receiver

part of transmitter circuitry

part of CODEC and audio circuitry

digital-to-analog converter

Transmitter

PIN
1)
Switch

analog-to-digital converter

LPF

Main Board

RF
analog
digital
asynchronous serial data
synchronous serial data

Frequency
Synthesizer
Custom
Logic

RISC
Proc.

FPGA

DSP

Flash
Memory

SRAM

Serial
Flash

Digital Board

Power Supply

CODEC
and Audio

Interface

Internal Options
Connector

Auxiliary
Connector

Control-Head
Connector

Power
Connector

Figure 2.10
Hardware architecture of the main board

Description

2.4.2

Software Architecture

Overview

Software plays an important role in the functioning of the radio. Some radio
functions such as the graphical user interface, processing of the analog and
digital signals, and the implementation of analog and digital radio
applications are completely implemented by software.
For a block diagram of the software architecture, refer to Figure 2.11 on
page 45.

Software Modules

The following software modules are stored on the digital board of the main
board:
■

FPGA image, which includes the software-implemented RISC processor
and the custom logic (the custom logic executes additional digital signal
processing)

■

boot code

■

radio application code

■

digital signal processing

■

radio application database and radio calibration database

The following software modules are stored on the control-head board with:
■

FPGA image, which includes the software-implemented RISC processor

■

boot code

■

control-head application code

■

control-head application database

Hardware and interface drivers are part of the boot code, the RISC code,
and—in case of the main board—the DSP code.

Description

TM9100 Service Manual
© Tait Electronics Limited August 2005

Database

Flash
Memory

Boot Code

Serial
Flash

Application Code

Software architecture

FPGA Image

Figure 2.11

FPGA

Serial Flash

FPGA Image

RISC Processor
Flash Memory

Control-Head Application Code

Boot Code

Boot Code
Radio Application
Code

Boot Code
Radio Application Code
Database
DSP Code

Custom Logic

DSP
DSP Code

Additional Digital
Signal Processing

RISC Proc.

SRAM

FPGA Image

SRAM

FPGA

Dynamic Memory
Dynamic
Memory

Software Start-Up

When the radio is turned on, the following processes are carried out on the
main board:
Note

This process describes the normal software start-up into normal
radio operation mode.

The FPGA image, which includes the RISC processor and the custom logic, is loaded from the serial flash to the FPGA.

The RISC processor executes the boot code, which carries out an
initialization and auto-calibration, and—in case of a fault—generates
an error code for display on the control head.

Normal radio operation starts with:
■

the RISC processor executing the radio application code,
including application software for the analog and/or digital modes

■

the DSP executing the DSP code for processing of digital signals
in analog and digital mode

■

the custom logic executing additional digital signal processing

TM9100 Service Manual
© Tait Electronics Limited August 2005

Description

When the radio is turned on, the following processes are carried out on the
control-head board:
1.

The FPGA image, which includes the RISC processor, is loaded from
the serial flash to the FPGA.

The RISC processor executes the boot code, which carries out an
initialization, and—in case of a fault—generates an error code for
display on the control head.

Normal radio operation starts with the RISC processor executing
■

the graphical user interface

■

the I/O processing

■

the user interface processing

During normal radio operation the radio body and control head
communicate via interface software, which is part of the radio and controlhead application software.
Software Shutdown

On shutdown, the programming and calibration data is stored in the
database, and power is removed from the radio.
Important

On power loss, any changes made to the programming or
calibration data may be lost.

Programming and
Calibration Files

One of the servicing tasks is the downloading and uploading of
programming and calibration files to the database. For more information,
refer to “Servicing Procedures” on page 139 and the online help of the
programming and calibration applications.

Software Upgrades

During servicing it may become necessary to upload software to a
replacement main board, control head, or control head board using the
Tools > Options > Download command of the programming application.
For more information, refer to the online help of the programming
application and to the technical notes accompanying the software files.

Description

TM9100 Service Manual
© Tait Electronics Limited August 2005

2.5
Overview

Operation in Receive Mode
This section describes the functioning of the transceiver in receive mode.
The operation of the transceiver is illustrated in Figure 2.12 on page 48
(analog mode) and Figure 2.13 on page 49 (digital mode).
These block diagrams show the hardware modules integrated with the
software modules:
■

hardware (transmitter, receiver, CODEC and audio)

■

RISC processor (on FPGA of digital board)

■

custom logic (on FPGA of digital board)

■

DSP (on digital board)

Note

The block diagrams for the analog and digital modes only differ in
the operation of the DSP.

The receive path consists of three major functional parts:
■

RF hardware

■

digital baseband processing

■

audio processing and signaling

Note

TM9100 Service Manual
© Tait Electronics Limited August 2005

The information flow on a digital radio can be categorized in two
forms, signaling (including user data) and voice. Whilst setting up
a call, signaling may be the only information transferred across the
air interface. Once a call has been established however, both signaling and voice information are transported. The signaling information continues throughout the call for the purpose of maintaining the call and possibly sending data information.

Description

Antenna

LPF

Dir.
Coup.

Description

Fin

Pwr
Ctrl

Bias

Front
End

PLL

VCXO

Loop
Filter

Digital
Downconverter

RX
AGC

2nd IF:
64 kHz
Second LO
UHF: 90.328 MHz
VHF: 42.928 MHz

VCO*

Quad
Demod

TCXO:
13.000 MHz

Hardware

Drv
/Ex

Phase
locked to
TCXO

1st
IF

IF:
UHF: 45.1 MHz
VHF: 21.4 MHz
FM
Demod

Ramp
Control

Frequency
Control

Triple-point
Equalization

Custom
Logic

Channel
LPF

Mag.

Deemphasis

Preemphasis

Key

System interface

Mic
FGA

Audio
PA

Power

Control
Head

Auxiliary

Control
Head

For UHF there are separate VCOs for RX and TX

(2) VHF configuration shown*

Mic
PGA

Hardware

Secondary
Volume
Control

(1) Noise blanker not shown

Notes

ALC

Side
Tones

Primary
Volume
Control

Digital-to-analog conversion

Tx
Interface

Optional
Processing

DSP

Optional
Processing

Rx
Interface

Analog-to-digital conversion

RISC Processor

Data and Signaling
Encoders

Audio
Filtering

Squelch

Data and Signaling
Decoders

Audio
Filtering

RSSI

RISC Processor

Figure 2.12
Transceiver operation in analog mode

TM9100 Service Manual
© Tait Electronics Limited August 2005

Antenna

LPF

Dir.
Coup.

TM9100 Service Manual
© Tait Electronics Limited August 2005

Fin

Pwr
Ctrl

Bias

Front
End

PLL

VCXO

Loop
Filter

Digital
Downconverter

RX
AGC

2nd IF:
64 kHz
Second LO
UHF: 90.328 MHz
VHF: 42.928 MHz

VCO*

Quad
Demod

TCXO:
13.000 MHz

Hardware

Drv
/Ex

Phase
locked to
TCXO

1st
IF

IF:
UHF: 45.1 MHz
VHF: 21.4 MHz
FM
Demod

Ramp
Control

Frequency
Control

Triple-Point
Equalization

Custom
Logic

Channel
LPF

Key

C4FM
Modulator

C4FM
Demod

RSSI

Signaling
Packets

Voice
Packets

Signaling
Packets

Vocoder

Mic
PGA

Mic
FGA

Hardware

Secondary
Volume
Control

For UHF there are separate VCOs for RX and TX

(2) VHF configuration shown*
System interface

Digital-to-analog conversion

Notes

ALC

Side
Tones

Primary
Volume
Control

(1) Noise blanker not shown

Tx
Interface

Vocoder

DSP

Tx
Signaling
FEC

Voice
FEC

Rx
Signaling
FEC

Rx
Interface

Analog-to-digital conversion

RISC Processor

Tx
Burst
Builder

Arbitrator

Rx
Burst
Builder

RISC Processor

Audio
PA

Control
Head

Auxiliary

Control
Head

Power

Figure 2.13
Transceiver operation in digital mode

Description

2.5.1

RF Hardware

PIN Switch

The RF PIN switch circuitry selects the RF path to and from the antenna
to either the Tx or Rx circuitry of the radio. In addition to the switching
functionality, the PIN switch is used to provide attenuation to the Rx front
end in high signal-strength locations.

Front End and
First IF

The front-end hardware amplifies and image-filters the received RF
spectrum, then down-converts the desired channel frequency to a first
intermediate frequency IF1 of 45.1MHz (UHF) or 21.4MHz (VHF) where
coarse channel filtering is performed. The first LO signal is obtained from
the frequency synthesizer and is injected on the low side of the desired
channel frequency for all bands. In receive mode, the modulation to the
frequency synthesizer is muted. See “Frequency Synthesizer” on page 57 for
a description of the frequency synthesizer. The output of the first IF is then
down-converted using an image-reject mixer to a low IF of 64kHz.

Quadrature
Demodulator

The LO for the image-reject mixer (quadrature demodulator) is synthesized
and uses the TCXO as a reference. This ensures good centring of the IF
filters and more consistent group-delay performance. The quadrature
demodulator device has an internal frequency division of 2 so the second
LO operates at 2 x (IF1+64kHz). The quadrature output from this mixer is
fed to a pair of ADCs with high dynamic range where it is oversampled at
256kHz and fed to the custom logic device.

Automatic Gain
Control

The AGC is used to limit the maximum signal level applied to the imagereject mixer and ADCs in order to meet the requirements for
intermodulation and selectivity performance. Hardware gain control is
performed by a variable gain amplifier within the quadrature demodulator
device driven by a 10-bit DAC. Information about the signal level is
obtained from the IQ data output stream from the ADCs. The control loop
is completed within the custom logic. The AGC will begin to reduce gain
when the combined signal power of the wanted signal and first adjacent
channels is greater than about -70dBm. In the presence of a strong adjacentchannel signal it is therefore possible that the AGC may start acting when
the wanted signal is well below -70dBm.

Noise Blanking
(B1 band only)

With the B1 band, a noise blanker can be selected to remove common
sources of electrical interference such as vehicle ignition noise. The noise
blanker functions by sampling the RF input to the receiver for impulse noise
and momentarily disconnecting the first LO for the duration of the impulse.
The response time of the noise blanker is very fast (tens of nanoseconds) and
is quicker than the time taken for the RF signal to pass through the frontend hardware, so that the LO is disabled before the impulse reaches the IF
stage where it could cause crystal filter ring.

Description

TM9100 Service Manual
© Tait Electronics Limited August 2005

2.5.2

Digital Baseband Processing

Custom Logic

The remainder of the receiver processing up to demodulation is performed
by custom logic. The digitized quadrature signal from the RF hardware is
digitally down-converted to a zero IF and channel filtering is performed at
baseband. Different filter shapes are possible to accommodate the various
channel spacings and data requirements. These filters provide the bulk of
adjacent channel selectivity for narrow-band operation. The filters have
linear phase response so that good group-delay performance for data is
achieved. The filters also decimate the sample rate down to 48kHz.
Custom logic also performs demodulation, which is multiplexed along with
AGC and amplitude data and fed via a single synchronous serial port to the
DSP. The stream is demultiplexed and the demodulation data used as an
input for further audio processing.

Noise Squelch

The noise squelch process resides in the DSP. The noise content above and
adjacent to the voice band is measured and compared with a preset
threshold. When a wanted signal is present, out-of-band noise content is
reduced and, if below the preset threshold, is indicated as a valid wanted
signal.

RSSI

Receive signal strength is measured by a process resident in the DSP.
This process obtains its input from the demodulator (RF signal magnitude
value) and from the AGC (present gain value). With these two inputs and a
calibration factor, the RF signal strength at the antenna can be accurately
calculated.

Calibration

The following items within the receiver path are factory-calibrated:
■

front-end tuning

■

AGC

■

noise squelch

■

RSSI

Information on the calibration of these items is given in the on-line help
facility of the calibration application.

TM9100 Service Manual
© Tait Electronics Limited August 2005

Description

2.5.3

Audio Processing and Signaling

Audio Processing
(Analog Mode)

Raw demodulated data from the receiver is processed within the DSP.
The sample rate at this point is 48kHz with signal bandwidth limited only
by the IF filtering. Scaling (dependent on the bandwidth of the RF channel)
is then applied to normalize the signal level for the remaining audio
processing. The sample rate is decimated to 8kHz and 0.3 to 3kHz bandpass
audio filtering is applied. De-emphasis is then applied to cancel out the
receive signals pre-emphasized response and improve signal to noise
performance. Optional processing such as decryption or companding is then
applied if applicable.

Data and Signaling
Decoders
(Analog Mode)

The data and signaling decoders obtain their signals from various points
within the audio processing chain. The point used depends on the decoders’
bandwidth and whether de-emphasis is required. Several decoders may be
active simultaneously.

Side Tones

Side tones are summed in at the end of the audio processing chain. These are
tones that provide some form of alert or give the user confidence an action
has been performed. The confidence tones may be generated in receive or
transmit mode. The sidetone level is a fixed proportion (in the order of
-10dB) relative to full scale in the receive path.

C4FM Demodulator
(Digital Mode)

Once the received signal is FM demodulated, it enters the C4FM demodulator. Once synchronization has been acquired, the received signals
should exist as four possible frequencies. These frequencies are translated
directly into received symbols ready to be passed to the burst builder.

Rx Burst Builder
(Digital Mode)

The job of the burst builder is to dismantle the received burst. The burst
builder can only receive an incoming burst once synchronization has been
achieved by the C4FM modem. The synchronization sequence itself does
not contain meaningful signaling payload and is discarded by the burst
builder. The payload content of the burst is dismantled and routed to the
appropriate signaling FEC or voice FEC task for decoding. The dismantling
process is the reverse of the construction process performed by the burst
builder.

Rx Signaling FEC
(Digital Mode)

Prior to transmission, signaling information such as the network identifier
was protected with forward error correction. Upon reception, the signaling
may contain errors. If the number of errors is limited they can be corrected
to recover the originally transmitted signaling.

Rx Vocoder FEC
(Digital Mode)

The 144 bits received from the burst builder are de-interleaved on a frame
by frame basis. An attempt is made to decode the 88 vocoder bits using the
complementary process to that used in the encoder. An indication of the
success of the decoder is produced. If the FEC algorithm is unable to decode
correctly, a recommendation is made to the vocoder, depending on the
severity of the errors, to either guess what the frame should be, to repeat the
last frame, or to mute for this frame.

Description

TM9100 Service Manual
© Tait Electronics Limited August 2005

Rx Vocoder
(Digital Mode)

The 88 bits from the FEC are decoded to generate the fundamental
frequency of the frame, the voiced/unvoiced decisions for each frequency
band, and the spectral amplitudes. 20ms of speech is synthesized from this
information, and is interpolated between the previous frame and the next
frame to minimize any artefacts due to the transition from one frame to the
next.

Arbitration
(Digital Mode)

Transmission over the air interface from a radio terminal is governed by
channel access procedures. The radio must monitor the Status Symbols on
the inbound channel, and wait for the status to indicate that the channel is
free to use (idle) before transitioning to transmit mode. The channel access
procedures are supervised by various timers. Normally, these procedures
must be applied before transitioning from receive mode to transmit mode.
However, they may be overridden under emergency conditions.

CODEC

The combined audio and side-tone signal is converted to analog form by a
16-bit DAC with integral anti-alias filtering. This is followed by a
programmable-gain amplifier with 45dB range in 1.5dB steps, that performs
primary volume control and muting. The DAC and primary volume control
are part of the same CODEC device (AD6521).

Output to Speakers

The output of the CODEC is fed to an audio power amplifier via a
secondary volume control and to the control head via a buffer amplifier.
The output configuration of the audio power amplifier is balanced and
drives an internal speaker in non-remote control-head configuration and,
optionally, an external speaker. The speaker loads are connected in parallel
rather than being switched. The power delivered to each speaker is limited
by its impedance. The internal speaker has 16Ω impedance whereas the
external speaker can be as low as 4 Ω.

Volume Control
Configurations

There are two volume controls in the radio but only one is active at any time
when audio is being output to the speaker(s). The inactive volume control
is set to maximum. For non-remote control-head configuration, the
primary volume control is active. For remote control-head configuration,
the secondary volume control is active. This enables fixed level audio feed
to the remote control head, and independent volume control of the external
speaker and the speaker of the remote control head.

TM9100 Service Manual
© Tait Electronics Limited August 2005

Description

2.6

Operation in Transmit Mode

Overview

This section describes the functioning of the transceiver in transmit mode.
The operation of the transceiver is illustrated in Figure 2.12 on page 48
(analog mode) and Figure 2.13 on page 49 (digital mode).
These block diagrams show the hardware modules integrated with the
software modules:
■

hardware (transmitter, receiver, CODEC and audio)

■

RISC processor (on FPGA of digital board)

■

custom logic (on FPGA of digital board)

■

DSP block (on digital board)

Note

The block diagrams for the analog and digital modes only differ in
the operation of the DSP.

The transmit path consists of three major functional parts:
■

audio processing and signaling

■

frequency synthesizer

■

RF transmitter

Note

Description

TM9100 Service Manual
© Tait Electronics Limited August 2005

2.6.1

Audio Processing and Signaling

Microphone Input

The input to the transmitter path begins at the microphone input. There are
two microphone sources: a fist microphone connected to the control head
and an auxiliary microphone connected via the auxiliary or external options
connector. Only electret-type microphones are supported. Support for
optional dynamic fist microphones is facilitated by a hardware amplifier and
filter in the control head, and must be activated in the programming
software.

Analog Processing
of the Microphone
Input

The CODEC (AD6521) performs microphone selection and amplification.
The microphone amplifier consists of a fixed gain amplifier of 16dB
followed by a programmable-gain amplifier with 0 to 22dB gain.
The amplified microphone signal is converted to a digital stream by a 16-bit
ADC with integral anti-alias filtering (0.1 to 3.2kHz). The digital stream is
transported to the DSP for further audio processing.

Automatic Level
Control

The ALC follows and is used to effectively increase dynamic range by
boosting the gain of the microphone pre-amplifier under quiet conditions
and reducing the gain under noisy acoustic conditions. The ALC function
resides in the DSP and controls the microphone-programmable gain
amplifier in the CODEC. The ALC has a fast-attack (about 10ms) and
slow-decay (up to 2s) gain characteristic. This characteristic ensures that the
peak signal level is regulated near full scale to maximize dynamic range.

DSP Audio
Processing
(Analog Mode)

The output of the automatic level control provides the input to the DSP
audio processing chain at a sample rate of 8kHz. Optional processing such
as encryption or companding is done first if applicable. Pre-emphasis, if
required, is then applied. The pre-emphasized signal is hard limited to
prevent overdeviation and filtered to remove high frequency components.
The sample rate is then interpolated up to 48kHz and scaled to be suitable
for the frequency synthesizer.

Data and Signaling
Encoders
(Analog Mode)

The data and signaling encoders inject their signals into various points
within the audio processing chain. The injection point depends on the
encoders bandwidth and whether pre-emphasis is required.

Tx Vocoder
(Digital Mode)

The IMBE vocoder block takes audio samples in blocks of 20ms, analyses
them and compresses them down to 88 bits. If there is no speech content in
the segment, the vocoder produces silence. If speech is detected in the
segment, the content of the segment is split into a variable number of
frequency bands (max. 12) and a voiced/unvoiced decision is made for each
band. It also estimates the pitch of the segment of speech and determines the
spectral amplitudes of the voiced frequency bands.

TM9100 Service Manual
© Tait Electronics Limited August 2005

Description

Tx Vocoder FEC
(Digital Mode)

The 88 bits from the vocoder have 56 bits of parity added to them. Different
amounts of protection are afforded to the vocoder parameters, depending on
their relative importance. Four blocks of 12 bits are given highest priority
and are each encoded by (23,12) Golay codes. Three blocks of 11 bits are
afforded less protection and are encoded by (15,11) Hamming codes.
The final 7 bits are unprotected. Finally all 144 bits are interleaved to spread
the affect of bursts errors throughout the frame, and sent to the Burst
Builder.

Tx Signaling FEC
(Digital Mode)

In the same way as voice packets are protected using forward error
correction, so too is the signaling information (control and data).
One example is the network identifier which is protected using a powerful
BCH (Bose-Chandhuri-Hocquenghem) error code.

Tx Burst Builder
(Digital Mode)

It is the nature of a digital radio transmission that the information is
structured into bursts. An air interface burst can take several forms. Every
burst consists of a frame synchronization sequence and Network identifier,
followed by the main body of the burst, the content of which depends upon
the type of burst. For a voice burst, it comprises a fixed number of voice
packets with control signaling and low speed data interspersed. For a data or
control burst, it comprises a variable number of data blocks. Additionally,
every air interface burst is expanded with a status symbol after every 70 bits
of information. These status symbols are used for channel access procedures.
It is the job of the burst builder to construct the air interface burst using
FEC-encoded code words delivered to it by the signaling FEC and voice
FEC. The burst is then passed to the C4FM modulator.

Arbitrator
(Digital Mode)

Transmission over the air interface from a radio terminal is governed by
channel access procedures. The radio must monitor the status symbols on
the inbound channel, and wait for the status to indicate that the channel is
free to use (idle) before transitioning to transmit mode. The channel access
procedures are supervised by various timers. Normally, these procedures
must be applied before transitioning from receive mode to transmit mode.
However, they may be overridden under emergency conditions.

C4FM Modulator
(Digital Mode)

The burst builder creates a symbol stream that must be modulated onto the
RF carrier. Four possible symbols can be transmitted. They are passed
through a shaping filter defined by the APCO standard which limits the
spectral occupancy on air. The four symbols are transmitted at pre-defined
frequency deviations from the carrier.

Description

TM9100 Service Manual
© Tait Electronics Limited August 2005

2.6.2

Frequency Synthesizer

Introduction

Frequency Control
Loop

As shown in Figure 2.12, the frequency synthesizer consists of two main
parts:
■

FCL

■

RF PLL, comprising RF PLL device, loop filter, VCO, and VCO output
switch

The FCL consists of the following:
■

TCXO

■

mixer

■

loop filter

■

VCXO

■

frequency control block

The FCL provides the reference frequency for the RF PLL. The FCL
generates a high-stability reference frequency that can be both modulated
and offset in fine resolution steps.
RF PLL

■

The RF PLL consists of the following:

■

RF PLL device

■

loop filter

■

VCO

■

VCO output switch

The RF PLL has fast-locking capability but coarse frequency resolution.
This combination of control loops creates improved frequency generation
and acquisition capabilities.
Note that patents are pending for several aspects of the synthesizer design.
Operation of
Control Loop

The RF PLL is a conventional integer-N-type design with frequency
resolution of 25kHz. In transmit mode, the loop locks to the transmit
frequency, whereas in receive mode, it locks to the receive frequency minus
the first IF frequency.
Initially, the VCO generates an unregulated frequency in the required range.
This is fed to the PLL device (ADF4111) and divided down by a
programmed ratio to approximately 25kHz. The reference frequency input
from the FCL is also divided down to approximately 25kHz. The phase of
the two signals is compared and the error translated into a DC voltage by a
programmable charge pump and dual-bandwidth loop filter. This DC signal
is used to control the VCO frequency and reduce the initial error. The loop
eventually settles to a point that minimizes the phase error between divided
down reference and VCO frequencies. The net result is that the loop
“locks” to a programmed multiple of the reference frequency.

TM9100 Service Manual
© Tait Electronics Limited August 2005

Description

The FCL generates an output of 13.012MHz±4kHz. Initially, a voltage
controlled crystal oscillator (VCXO) produces a quasi-regulated frequency
in the required range. The VCXO output is fed to a mixer where it is mixed
with the 13.000MHz TCXO frequency. The mixer, after low-pass filtering
to remove unwanted products, produces a frequency of 12kHz nominally.
This is converted to digital form and transported to the frequency control
block in the custom logic.
The frequency control block compares the mixer output frequency to a
reference generated by the digital clock and creates a DC error signal.
A programmed offset is also added. This error signal is converted to analog
form and used to control the VCXO frequency and reduce the initial error.
Once settled, the loop “locks” to the TCXO frequency with a programmed
offset frequency. The FCL output therefore acquires the TCXO's frequency
stability.
Modulation

The full bandwidth modulation signal is obtained from the DSP in digital
form at a sample rate of 48kHz. In traditional dual-point modulation
systems the modulation is applied, in analog form, to both the frequency
reference and the VCO in the RF PLL, combining to produce a flat
modulation response down to DC. Reference modulation is usually applied
directly to the TCXO.
In the system employed in the TM9100 radio, the frequency reference is
generated by the FCL, which itself requires dual-point modulation injection
to allow modulation down to DC. With another modulation point required
in the RF PLL, this system therefore requires triple-point modulation.
The modulation signals applied to the FCL are in digital form while for the
RF PLL (VCO) the modulation signal is applied in analog form.
The modulation cross-over points occur at approximately 30 and 300Hz as
determined by the closed loop bandwidths of the FCL and RF PLL
respectively.

Frequency
Generation

The RF PLL has a frequency resolution of 25kHz. Higher resolution
cannot be achieved owing to acquisition-time requirements and so for any
given frequency the error could be as high as ±12.5kHz. This error is
corrected by altering the reference frequency to the RF PLL. The FCL
supplies the reference frequency and is able to adjust it up to ±300ppm with
better than 0.1ppm resolution (equivalent to better than 50Hz resolution at
the RF frequency). The FCL offset will usually be different for receive and
transmit modes.

Fast Frequency
Settling

Both the FCL and RF PLL employ frequency-acquisition speed-up
techniques to achieve fast frequency settling. The frequency-acquisition
process of the FCL and RF PLL is able to occur concurrently with minimal
loop interaction owing to the very large difference in frequency step size
between the loops.

Description

TM9100 Service Manual
© Tait Electronics Limited August 2005

Frequency
Acquisition of
RF PLL

In the RF PLL the loop bandwidth is initially set to high by increasing the
charge-pump current and reducing time constants in the loop filter.
As a result, settling to within 1kHz of the final value occurs in under 4ms.
In order to meet noise performance requirements the loop parameters are
then switched to reduce the loop bandwidth. There is a small frequency kick
as the loop bandwidth is reduced. Total settling time is under 4.5ms.

Frequency
Acquisition of FCL

The FCL utilizes self-calibration techniques that enable it to rapidly settle
close to the final value while the loop is open. The loop is then closed and
settling to the final value occurs with an associated reduction in noise.
The total settling time is typically less than 4ms.

Calibration

The following items are calibrated in the frequency synthesizer:
■

nominal frequency

■

KVCO

■

KVCXO

■

VCO deviation

Calibration of the nominal frequency is achieved by adding a fixed offset to
the FCL nominal frequency; the TCXO frequency itself is not adjusted.
The items KVCO and KVCXO are the control sensitivities of the RF VCO
(in MHz/V) and VCXO (in kHz/V) respectively. The latter has
temperature compensation.

2.6.3

RF Transmitter

RF Power Amplifier
and Switching
(50W/40W Radio)

The RF power amplifier and exciter of the 50W/40W radio is a five-stage
line-up with approximately 40dB of power gain. The output of the
frequency synthesizer is first buffered to reduce kick during power ramping.
The buffer output goes to a discrete exciter that produces approximately 300
to 400mW output. This is followed by an LDMOS driver producing up to
8W output that is power-controlled. The final stage consists of two parallel
LDMOS devices producing enough power to provide 40 to 50W at the
antenna.

RF Power Amplifier
and Switching
(25W Radio)

The RF power amplifier of the 20W radio is a four-stage line-up with
approximately 37dB of power gain. The output of the frequency synthesizer
is first buffered to reduce kick during power ramping. The buffer output
goes to a broad-band exciter IC that produces approximately 200mW
output. This is followed by an LDMOS driver producing up to 2W output
that is power-controlled. The final stage consists of two parallel LDMOS
devices producing enough power to provide 25W at the antenna.

Output of RF Power
Amplifier

The output of the RF power amplifier passes through a dual-directional
coupler, used for power control and monitoring, to the PIN switch.
The PIN switch toggles the antenna path between the receiver and
transmitter in receive and transmit modes respectively. Finally, the output is
low-pass-filtered to bring harmonic levels within specification.

TM9100 Service Manual
© Tait Electronics Limited August 2005

Description

Power Control

The steady-state power output of the transmitter is regulated using a
hardware control loop. With the 50W/40W radio, the sum of the forward
power output from the RF power amplifier and reverse power reflected from
the load is sensed by the directional coupler and fed back to the power
control loop. With the 25W radio, the forward power output from the RF
power amplifier is sensed by the directional coupler and fed back to the
power control loop. The PA output power is controlled by varying driver
gate bias voltage that has a calibrated maximum limit to prevent overdrive.
The power control signal is supplied by a 13-bit DAC driven by custom
logic.

Ramping

Power ramp-up consists of two stages:
■

bias

■

power ramping

The timing between these two stages is carefully controlled in order to
achieve the correct overall wave shape and meet transient ACP
specifications. A typical ramping waveform is shown in Figure 2.14.
Figure 2.14

Typical ramping waveforms
Power
Bias Power
ramp ramp

Power Bias
ramp ramp
High power
Low power

Time

The timing between these two stages is critical to achieving the correct
overall wave shape in order to meet the specification for transient ACP
(adjacent channel power).
Bias Ramp-Up

The steady-state final-stage bias level is supplied by an 8-bit DAC
programmed prior to ramp-up but held to zero by a switch on the DAC
output under the control of a TX INHIBIT signal. Bias ramp-up begins upon
release by the TX INHIBIT signal with the ramping shape being determined by
a low-pass filter. Owing to power leakage through the PA chain, ramping
the bias takes the PA output power from less than –20dBm for the
50W/40W or –10dBm for the 25W radio to approximately 25dB below
steady-state power.

Power Ramp-Up

The power ramp signal is supplied by a 13-bit DAC that is controlled by
custom logic. The ramp is generated using a look-up table in custom logic

Description

TM9100 Service Manual
© Tait Electronics Limited August 2005

memory that is played back at the correct rate to the DAC to produce the
desired waveform. The ramp-up and ramp-down waveforms are produced
by playing back the look-up table in forward and reverse order respectively.
For a given power level the look-up table values are scaled by a steady-state
power constant so that the ramp waveform shape remains the same for all
power levels.
PIN Switch

TM9100 Service Manual
© Tait Electronics Limited August 2005

Description

TM9100 Service Manual
© Tait Electronics Limited August 2005

Circuit Descriptions

Introduction

This section describes and illustrates the circuitry of the main board and the
control-head board.
The main board is decided into the following circuitry modules:
■

transmitter

■

receiver

■

frequency synthesizer (including FCL)

■

CODEC and audio

■

power supply

■

interface

■

digital board

Figure 3.1 gives an overview of the of the circuitry modules of the main
board and shows how they are interconnected.
Sample Schematics

For up-to-date schematics refer to the relevant PCB information.

TM9100 Service Manual
© Tait Electronics Limited August 2005

Circuit Descriptions

RF Connector

Circuit Descriptions
Receiver

part of transmitter circuitry

part of CODEC and audio circuitry

digital-to-analog converter

Transmitter

PIN
1)
Switch

analog-to-digital converter

LPF

Main Board

RF
analog
digital
asynchronous serial data
synchronous serial data

Frequency
Synthesizer
Custom
Logic

RISC
Proc.

FPGA

DSP

Flash
Memory

SRAM

Serial
Flash

Digital Board

Power Supply

CODEC
and Audio

Interface

Internal Options
Connector

Auxiliary
Connector

Control-Head
Connector

Power
Connector

Figure 3.1
Main board hardware architecture

TM9100 Service Manual
© Tait Electronics Limited August 2005

3.1

Transmitter Circuitry

Introduction

For a block diagram of the transmitter circuitry, refer to Figure 3.2.
The transmitter circuitry is different for the 50W/40W radios and the 25W
radios, and the different bands.

Exciter

With the 50W/40W radio, the discrete-component exciter is designed for
specific bands (UHF or VHF). It is made up of Q3501, Q3502, and Q3505,
which amplify the signal provided by the frequency synthesizer from its level
of 7 to 10dBm up to 24dBm for the frequency bands 136 to 174MHz and
400 to 520MHz.
With the 25W radio, the broadband exciter is a common element in all the
bands, as it operates across all frequencies from 66 to 940MHz. It is made
up of Q300 and Q303, which amplify the signal provided by the frequency
synthesizer from its level of 7 to 10dBm up to 24.5dBm for the frequency
band from 66 to 530MHz and slightly less than this for the bands covering
530 to 940MHz.
The exciter operates in full saturation, thereby maintaining a constant
output power independent of the varying input power level supplied by the
synthesizer.

Power Amplifier

The power amplifier comprises the driver amplifier Q306 and two paralleled
final devices Q309 and Q310.
With the 50W/40W radio, the signal from the exciter is amplified by Q306
to a power level of approximately 2W (VHF) using a PD55003 and about
3W (UHF) using a PD55008. The resulting signal is then amplified by
Q309 and Q310 to produce a typical output power of 90W at 155MHz and
65W across the UHF band, when measured after the series capacitors
(C348, C349, C350) at the start of the directional coupler.
With the 25W radio, the 24.5dBm signal from the exciter is reduced by a
band-dependent pi-attenuator and is amplified by Q306. The resulting
signal is then amplified a second time by Q309 and Q310 to produce a
typical output power of 42W when measured after the series capacitors
(C348, C349, C350) at the start of the directional coupler.
The high-level RF signal passes via the directional coupler, the transmitreceive PIN switch, and the LPF, through to the antenna. The LPF is used
to attenuate unwanted harmonic frequencies.

Power Control Loop

Calibration is used to adjust the power control loop, thus setting the output
of the transmitter to one of four preferred power levels:
■

10, 15, 25, and 50 watts (VHF), and
10, 15, 20, and 40 watts (UHF) for 50W/40W radios

■

1, 5, 12 and 25 watts (all bands) for 25W radios

TM9100 Service Manual
© Tait Electronics Limited August 2005

Circuit Descriptions

Receiver

RF
Connector

Interface

AGND

PIN
Switch

synchronous serial data

asynchronous serial data

digital

clock

analog

Signal Types:

TX RX RF

LPF

Transmitter

Reverse Power
Buffer Amplifier
(40W/50W only)

Forward Power
Buffer Amplifier

Directional
Coupler

Buffer Amplifier

Power
Control

Temperature
Sensor

Thermal
Coupling

Driver

Shaper
and Level
Shifter

Bias
Limiter

Exciter

Crowbar

TX INH

Switch

Shaping
Filter

OR Gate

TX REV PWR

TX FWD PWR

TX TEMP

CDC TX PWR CTL

CDC TX FIN BIAS2

CDC TX FIN BIAS1

CDC TX DRV BIAS

SYN TX LO

SYN LOCK

DIG SYN EN

DIG TX INH

+13V8 BATT

+9V0 TX

CODEC
and
Audio

Frequency
Synthesizer

Digital
Board

Power
Supply

Figure 3.2
Block diagram of the transmitter circuitry

TM9100 Service Manual
© Tait Electronics Limited August 2005

The loop maintains these power settings under changing environmental
conditions. The control mechanism for this loop is via the DAC IC204 and
one of the operational amplifiers making up IC301. The power control loop
will be inhibited if for any reason an out-of-lock signal is detected from the
synthesizer. This ensures that no erroneous signals are transmitted at any
time.
With the 50W/40W radio, the power control loop processes the voltages
from the forward and reverse power sensors in the directional coupler.
This signal is fed to the buffer and a band-limited operational amplifier back
to the gate of Q306. In this way, the transmitter is protected against bad
mismatches.
With the 25W radio, the power control loop senses the forward power by
means of the diode D304. This signal is fed to the buffer and a band-limited
operational amplifier back to the gate of Q306.
A voltage clamp (one of the operational amplifiers of IC301) for Q306 limits
the maximum control-loop voltage applied to its gate.
Directional
Coupler

With the 50W/40W radio, the directional coupler actively senses the
forward power and the reverse power, and feeds them back to the powercontrol circuit.
With the 25W radio, the directional coupler actively senses the forward
power and feeds it back to the power-control circuit. If the directional
coupler detects too much reverse power, indicating a badly matched
antenna, the transmitter will be reduced to the lowest power setting.

Temperature Sensor

For added protection, a temperature sensor ensures that the transmitter
power is reduced to very low levels should a temperature threshold be
exceeded. If the temperature does not decrease, the transmitter is switched
off.

TM9100 Service Manual
© Tait Electronics Limited August 2005

Circuit Descriptions

3.2

Receiver Circuitry

Introduction

For a block diagram of the receiver circuitry, refer to Figure 3.3.
The receiver is of the triple-conversion superheterodyne type. The first two
IF stages are implemented in hardware; the third stage is implemented in the
FPGA (field-programmable gate array) of the digital board. The FPGA also
carries out the demodulation of the received signals.

Front-End Circuitry

The front-end circuitry is a standard varicap-tuned singlet (band-pass filter),
followed by an LNA (low-noise amplifier), and then a varicap-tuned
doublet (image filter). The varicap tuning voltage CDC RX FE TUNE is provided
by a DAC, with voltages calculated from a calibration table stored in nonvolatile memory. The two varicap-tuned filters need to be calibrated to
ensure that maximum sensitivity is achieved.

First Mixer

The first mixer is a standard diode-ring mixer with SMD (surface-mount
device) baluns and a quadruple SMD diode. For the VHF band the receiver
includes a circuit for suppressing ignition noise. This circuit momentarily
removes the LO signal from the mixer when an ignition noise pulse is
detected. The ignition-noise suppressor is selectable on a per-channel basis
when the radio is programmed.

First IF Stage and
Second Mixer

The first IF stage consists of a crystal channel filter (BPF1), followed by an
IF amplifier, and then another crystal filter (BPF2). The second mixer is an
IC quadrature mixer with an internal AGC amplifier. This IC has a divideby-two function on the LO input in order to provide the quadrature LO
frequencies required internally. The second LO frequency is synthesized by
an integer PLL (IC403), which uses the TCXO frequency SYN RX OSC
(13.0000 MHz) as its reference.

Frequencies
of IF Stages

The frequency of the first IF stage depends as follows on the frequency band
of the radio:
■

B1 band: 21.400029MHz

■

H5, H6, and H7 bands: 45.100134MHz

The above are nominal values; the actual frequency will differ by a small
amount depending on the exact initial frequency of the TCXO.
The frequency of the second IF stage will always be precisely 64.000kHz
once the TCXO calibration has been completed. (The TCXO calibration
does not adjust the TCXO frequency, but instead adjusts the VCXO
frequency, which in turn adjusts the VCO or first LO frequency as well as
the frequency of the first IF stage. The second LO frequency remains fixed.)
The third IF stage is completely within the FPGA and is not accessible.

Circuit Descriptions

TM9100 Service Manual
© Tait Electronics Limited August 2005

Attenuator

Image Filter

Transmitter

Noise
Blanker
(VHF only)

LNA

synchronous serial data

asynchronous serial data

clock
digital

analog

Signal Types:

TX RX RF

TM9100 Service Manual
© Tait Electronics Limited August 2005
Image Filter

Mixer

Switch
(VHF only)

Receiver

SYN RX OSC

Frequency
Synthesizer

SYN RX LO1

PLL

First IF
BPF 1

Loop Filter

IF Amplifier

First IF
BPF 2

VCO

Quadrature
Demodulator

Bias
Network

DIG RX NB EN

DIG SYN SPI CLK

DIG SYN SPI DO

RX DIG LD

DIG RX LE

DIG RX EN

AGND

CDC RX PIN AGC

CDC RX FE TUNE

CDC RX AGC

RX CDC QN

RX CDC QP

RX CDC IN

RX CDC IP

CDC RX VREF

+3V0 AN

+3V0 RX

Digital
Board

Interface

CODEC
and
Audio

Power
Supply

Figure 3.3
Block diagram of the receiver circuitry

Circuit Descriptions

Demodulation

Demodulation takes place within the FPGA. Demodulated audio is passed
to the DSP of the digital board for processing of the receiver audio signal.
Raw demodulated audio can be tapped out from the DSP for use with an
external modem. The modem may be connected to the auxiliary connector
or to the external options connector when an internal options board is
fitted.

Automatic Gain
Control

The receiver has an AGC circuit to enable it to cover a large signal range.
Most of the circuit functions are implemented in the FPGA. The FPGA
passes the AGC signal to the CODEC IC204 for output from pin 14
(IDACOUT) and thence via IC201 as the signal CDC RX AGC to pin 23 of the
quadrature mixer IC400. As the antenna signal increases, the AGC voltage
decreases.

Channel Filtering

The channel filtering is split between the first and third IF stages.
The channel filtering circuit in the first IF stage comprises a pair of two-pole
crystal filters. The first filter has a 3dB bandwidth of 12kHz, and the second
a 3dB bandwidth of 15kHz. Most of the channel filtering, however, is
implemented in the FPGA. When the radio is programmed, the different
filters are selected as assigned by the channel programming. The selectable
filters plus the fixed crystal filters result in the following total IF 3dB
bandwidths:
■

wide channel spacing

: 12.6kHz

■

medium channel spacing: 12.0kHz

■

narrow channel spacing : 7.8kHz

(The FPGA runs from the DIG SYS CLK signal, which has a frequency of
12.288MHz.) The receiver requires the TCXO calibration to be completed
to ensure that the channel filtering is centered, thereby minimizing
distortion.
Received Signal
Strength Indication

The RSSI is calculated in the FPGA and DSP, and can be passed as an analog
voltage to the internal options interface and the external auxiliary interface.
To obtain an accurate estimate of the RSSI (over the signal level and
frequency), it is necessary to calibrate the AGC characteristic of the receiver
and the front-end gain versus the receive frequency.

Front-End AGC
Control

The receiver has an FE AGC circuit to enable it to handle large receiver
signals with minimal receiver distortion. This is very important for the
correct operation of the C4FM modem (P25 modulation). FE AGC is
controlled by an algorithm which monitors the RSSI and configures the
DAC to turn on the FE attenuation via the receive pin diode of the PIN
switch.

Circuit Descriptions

TM9100 Service Manual
© Tait Electronics Limited August 2005

3.3

Frequency Synthesizer Circuitry

Introduction

For a block diagram of the frequency synthesizer circuitry, refer to
Figure 3.4.
The frequency synthesizer includes an active loop filter, one or two VCOs
and buffer amplifiers, and a PLL IC. The last-named uses conventional
integer-N frequency division and includes a built-in charge pump. Speedup techniques ensure a transmit-receive settling time of less than 4.5ms
while retaining low noise characteristics in static operation.

Power Supplies

Several power supplies are used by the frequency synthesizer owing to a
combination of performance requirements and the availability of suitable
components. The PLL IC includes analog and digital circuitry and uses
separate power supplies for each section. The digital section is run on 3V,
while the analog section is run on approximately 5V. The VCOs and buffer
amplifiers run off a supply of about 5.3V. The active loop filter requires a
supply of 14 to 15V, and a reference voltage of approximately 2.5V.

Performance
Requirements

Low noise and good regulation of the power supply are essential to the
performance of the synthesizer. A 6V regulator IC provides good line
regulation of the 9V supply and good load regulation. Good regulation of
the power-supply line and load is essential for meeting the transient ACP
requirements. The regulator output voltage is electrically noisy, however,
and filtering is essential. Filtering of the power supply is achieved with two
capacitance multipliers (Q508 and C585 for the VCO supply, and Q512 and
C579 for the PLL and loop-filter supply). The VCO (or VCOs) use a
separate capacitance multiplier because these multipliers have poor load
regulation and the VCOs impart sufficient load transients to warrant a
separate supply.

Effect of Tuning
Range

For reasons of noise performance, the VCOs are designed to be tuned
within a range of 2 to 12V. Active tuning circuitry is required. An active
loop filter incorporating an IC operational amplifier achieves this range with
a suitable power supply voltage. Normal synthesizer switching behavior
involves overshoot, which dictates that the tuning voltage range must extend
above and below the range of 2 to 12V. The 14V limit is a result of limits
on the working supply voltage of the IC operational amplifier.

Switch-mode Power
Supply

The power supply VCL SUPPLY for the active loop filter is provided by a
SMPS, which is in turn powered by 9V. The SMPS consists of an oscillator
(switching circuit) and a detector. The output voltage is monitored by a
feedback circuit that controls the DC bias of the switching circuit to
maintain a constant output voltage.

Synthesizer
Circuitry

The essential function of the PLL frequency synthesizer is to multiply a
25kHz reference frequency to give any desired frequency that is an integer
multiple of 25kHz. There are some constraints imposed by the capabilities
of the synthesizer hardware, especially the tuning range of the VCOs.

TM9100 Service Manual
© Tait Electronics Limited August 2005

Circuit Descriptions

Digital
Board

Receiver

Transmitter

SYN RX OSC

SYN RX LO1

SYN TX LO

synchronous serial data

asynchronous serial data

digital

clock

analog

Signal Types:

VCO 1

SYN DIG FREF

SYN LOCK

DIG SYN LATCH

DIG SYN FAST

DIG SYN EN

DIG SYN TR SW

DIG SYN SPI CLK

DIG SYN SPI DO

VCO (UHF only)

Buffer
Amplifiers
and
Coupler

TR Switch

VCO 2

5 V SWITCH

VCO (VHF only)

PLL

MOD

Coupler

DIG SYN TR SW

SYN RX LO1

SYN TX LO

TR SWITCH

MOD

PLL

Summer

+5 V DEC

5 V Switch

VCO
Supply
Filter

Loop
Filter

14 V
SMPS

Inverter

VCL SUPPLY

PLL

+5 V
VP

5V
VP SUPPLY

Mixer

Buffer Amplifier

TCXO

VCXO

LPF

Modulator
Buffer Amplifier

Frequency Synthesizer

AGND

CDC VCO MOD

SYN CDC LFV

SYN CDC FCL

CDC VCXO MOD

+3V0 AN

+6V0
+9V0

Interface

CODEC
and
Audio

Power
Supply

Figure 3.4
Block diagram of the frequency synthesizer circuitry

TM9100 Service Manual
© Tait Electronics Limited August 2005

Reference
Frequency

The 25kHz (approximate) reference is obtained by dividing the 13MHz
(approximate) output of the FCL. Any error in the FCL output frequency
will be multiplied by the synthesizer. Therefore, if the synthesizer is locked
but not the FCL, then the synthesizer output frequency will be wrong.
The FCL frequency division is performed by a digital counter inside the
PLL IC. The divider setting is constant.

VCO Frequency and
Output Power

The output frequency from the synthesizer is generated by a VCO.
The VCO frequency is tuned across the frequency range of the radio by
means of a DC control voltage, typically between 2V and 12V. The VCO
output power is amplified by a buffer amplifier. The power is low and varies
from band to band. The buffer output power depends on which mode—
receive or transmit—is used. In receive mode the output power should be
about 7dBm, whereas in transmit mode it should be about 9dBm.

Dual VCOs

Some variants of the synthesizer use two VCOs: one for receive and one for
transmit. Synthesizers with two VCOs share the same tuning signal.
Only one VCO is switched on at a time, and so the PLL IC will see only
one output frequency to tune. A portion of the RF output from the VCOs
is fed to the RF input of the PLL IC. The RF signal is divided by an integer
that would give 25kHz if the output frequency were correct.

Phase-locked Loop

The PLL IC compares the 25kHz reference and the divided VCO signal,
and the error is used to control the internal charge pump. The charge pump
is a current source that can sink or source current in proportion to the
frequency or phase error. The output is a series of 25kHz pulses with a
width that is dependent on the phase error. When the output frequency of
the synthesizer is correct, there is no error and the charge pump output will
become open circuit.

Active Loop Filter

The loop filter continuously integrates the current pulses from the charge
pump and produces a steady DC output voltage that tunes the VCO
(or VCOs). When the VCO frequency is correct, there is no frequency
error and therefore no charge-pump output, and so the loop filter’s output
voltage remains constant. If the frequency is too high or too low, the error
will result in the output of charge-pump current pulses (negative or positive
depending on the sign of the error). The loop filter’s output voltage will
change accordingly, causing the VCO frequency to change in proportion.
The synthesizer design is such that normally the VCO frequency will be
automatically corrected.

Re-tuning of VCO
Frequency

When the radio changes channels or switches between receive and transmit,
the VCO frequency must be changed. The rate at which the VCO is retuned is dependent on many factors, of which the loop filter is the main
factor. The loop filter is an integrator built around an operational amplifier.
The resistors and capacitors of the filter affect both the switching time and
the stability of the synthesizer; the values of these components have been
carefully selected to give optimum control characteristics.

TM9100 Service Manual
© Tait Electronics Limited August 2005

Circuit Descriptions

Speed-up
Techniques

To reduce the change-over time between transmit and receive, part-time
speed-up techniques have been implemented. Speed-up involves changing
some resistor values while simultaneously changing the PLL IC settings.
This process is implemented in hardware under software control in
conjunction with use of the synthesized reference input. The result is a
transmit-receive settling time of less than 4.5ms. (The switching time is
measured for a frequency change equal to the first IF plus 10MHz or 1MHz,
depending on the repeater offsets used for the band. This implies a
synthesizer transmit-receive change-over plus an offset of 1MHz or 10MHz
in less than 4.5ms. The ramp-up and ramp-down of the transmitter, which
totals 1ms, extends this change-over time to 5.5ms.)

Circuit Descriptions

TM9100 Service Manual
© Tait Electronics Limited August 2005

3.4

Frequency Control Loop

Introduction

The FCL is included in the block diagram of the frequency synthesizer
(see Figure 3.4).
The FCL forms part of the frequency-synthesizer module. The basis of the
FCL is a VCXO, which generates the reference frequency required by the
main PLL of the synthesizer.

Elements of
FCL Circuitry

The FCL is a simple frequency-locked loop. The circuitry consists of the
following elements:
■

VCXO (XL501, Q501, Q503)

■

TCXO (XL500)

■

buffer amplifier (IC500)

■

mixer (IC501)

■

low-pass filter (IC502, pins 5 to 7)

■

modulator buffer amplifier (IC502, pins 1 to 3)

The TCXO supplies a reference frequency of 13.0000MHz, which is
extremely stable, regardless of the temperature. The VCXO runs at a
nominal frequency of 13.0000MHz, and is frequency-locked to the TCXO
reference frequency.
Circuit Operation

The VCXO output is mixed with the TCXO output to create a nominal
difference (or offset) frequency SYN CDC FCL of 12.0kHz. The signal SYN CDC
FCL is fed via the CODEC IC502 in the CODEC circuitry to the FPGA on
the digital board. The FPGA detects the offset frequency, compares it with
the programmed offset frequency, and outputs a corresponding feedback
signal CDC VCXO MOD via IC205. The feedback signal is amplified and inverted
by the modulator buffer amplifier and output as the loop voltage for the
VCXO. With this design the VCXO frequency can be adjusted by very
small precise amounts, and because the loop is locked, the VCXO inherits
the temperature stability of the TCXO.

Modulation

The FCL modulation is implemented within the FPGA and appears at the
output of IC205, and therefore on the VCXO loop voltage. Consequently,
the VCXO is frequency modulated directly by the relevant modulation
information. The latter may be the microphone audio, an audio tap-in
signal, internal modem signals, or any combination of these.

TM9100 Service Manual
© Tait Electronics Limited August 2005

Circuit Descriptions

3.5

CODEC and Audio Circuitry

Introduction

For a block diagram of the CODEC and audio circuitry, refer to Figure 3.5.

A/D and D/A
Conversion

The analog-to-digital conversion and digital-to-analog conversion is
performed by the devices IC203, IC204 and IC205.

Device IC203

IC203 is an eight-channel DAC that provides control of transmitter biasing,
front-end tuning, and the output of analog RSSI signals. The digital input
data are fed to IC203 in synchronous serial form. Three of the DAC
channels are not used.

Device IC205

IC205 contains two CODECs. One is used by the FCL. The second is used
for auxiliary audio (input) and VCO modulation (output). The digital
section communicates with this device via a four-wire synchronous serial
interface.

Device IC204

IC204 contains base-band, voice-band and auxiliary CODECs and some
analog signal conditioning. The reference voltage (nominally 1.2V) for
these CODECs is provided internally by IC204 but is decoupled externally
by C228.

Base-band CODEC

The base-band CODEC handles the I and Q outputs (IRXP, IRXN, QRXP and
QRXN balls) of the receiver’s second IF stage. The analog signals are
differential and biased at 1.2V nominally. The digital section communicates
with this CODEC via a two-wire synchronous serial interface (BSDO and
BSOFS balls). The digital-to-analog conversion section of the base-band
CODEC is not used.

Voice-band CODEC

The voice-band CODEC handles the microphone and speaker signals.
The digital section communicates with this CODEC via a three-wire
synchronous serial interface (VSFS, VSDO and VSDI balls). IC204 also contains
voice-band filtering, pre-amplification and volume control.

Auxiliary CODEC

The auxiliary CODEC handles transmitter power control, receiver gain
control, auxiliary audio output and general analog monitoring functions.
The digital section communicates with this CODEC via a three-wire
synchronous serial interface (ASFS, ASDI and ASDO balls). The DAC used for
receiver gain control (IDACOUT ball) is a current output type. Current-tovoltage conversion is performed by R238. The full-scale output of 1.2V is
amplified by IC201 to approximately 3V as required by the receiver.

Audio Circuitry

The audio circuitry performs four functions:

■

output of audio signal for speaker

■

input of microphone audio signal

■

input of auxiliary audio signal

■

output of auxiliary audio signal

Circuit Descriptions

TM9100 Service Manual
© Tait Electronics Limited August 2005

Frequency
Synthesizer

Transmitter

SYN CDC FCL

CDC VCXO MOD

CDC VCO MOD

SYN CDC LFV

TX REV PWR

TX FWD PWR

TX TEMP

CDC TX PWR CTL

CDC TX DRV BIAS

CDC TX FIN BIAS2

DAC

CODEC 2

DIG CDC2 SDTI

CDC TX FIN BIAS1

DIG CDC2 SCLK

CDC RX FE TUNE

DIG CDC2 LRCK

CDC RX AGC

Level
Shifter

DIG DAC SPI DO

DIG RX EN

DIG DAC SPI CLK

RX CDC QN

CDC DIG VSDO

DIG CDC ARSM
CDC DIG VSFS

+1V8

Digital Board

CODEC 1

DIG CDC VSDI

RX CDC QP

CDC DIG BSDO

Receiver

CDC DIG BSOFS

RX CDC IN

LPF

Bias
Network

+2V3 FIL

2V3
Supply

Summer

Volume
Control

Audio PA

CODEC and Audio

Buffer
Amplifier

Voltage
Divider

DIG AUD CS

RX CDC IP

DIG AUD UD

CDC RX VREF

DIG AUD PA EN1

TM9100 Service Manual
© Tait Electronics Limited August 2005
DIG AUD PA EN2

synchronous serial data

Interface

Power
Supply

asynchronous serial data

digital

DIG RX EN

clock

PSU SYS RST

analog

Signal Types:

ITF AUD TAP IN

CDC RSSI

CDC AUD TAP OUT

ITF VOL WIP DC

ITF AUX MIC AUD

ITF CH MIC AUD

ITF RX BEEP IN

AUD ITF SPK–

AUD ITF SPK+

AGND

CDC RX AUD

+13V8 BATT

+2V5 CDC

+9V0

+3V3

+3V0 AN

Figure 3.5
Block diagram of the CODEC and audio circuitry

Circuit Descriptions

CDC DIG ASDO

PSU SYS RST

DIG CDC ASFS

DIG CDC ASDI

DIG DAC LATCH

DIG SYS CLK

CDC2 DIG SDTO

DIG RX EN

The sections of the circuitry concerned with these functions are described
below.
Audio Signal
for Speaker

The audio signal for the speaker is generated by IC204 (VOUTAUXP ball).
This signal is post-volume-control and has a pre-emphasized frequency
response. The signal is then processed by R218, R217 and C231
(50W/40W radios) or C205 (25W radios) to restore a flat frequency
response and reduce the signal level to that required by the audio power
amplifier.

Summing Circuit

The top of C231 (50W/40W radios) or C205 (25W radios) is where side
tones are summed in and the CDC RX AUD signal is obtained. C201 and R211
pre-emphasize and attenuate the side-tone signal to give a flat side-tone
frequency response and reduce the input to an appropriate level.

Buffer Amplifier

IC201 (pins 8 to 10) amplifies the signal at the top of C231 (50W/40W
radios) or C205 (25W radios) by 19dB and drives the CDC RX AUD system
interface line via C212 and R225. The capacitor C212 provides AC output
coupling and R225 ensures stability. The DC bias for this amplifier is
derived from IC204.

Audio Power
Amplifier

The signal at the top of C231 (50W/40W radios) or C205 (25W radios) is
fed via C204 to the audio power amplifier IC202. IC202 has 46dB of gain
and a differential output configuration. C209, C211, R252 and R253
ensure stability of the amplifier at high frequencies. When operational, the
output bias voltage for IC202 is approximately half the radio supply voltage.
When not operational, the output becomes high impedance.

Control of Audio
Power Amplifier

Power up, power down, and muting of IC202 is controlled by two signals
from the digital section, DIG AUD PA EN1 and DIG AUD PA EN2. The network
consisting of Q200, Q201, R200 to R206, R210 and R250 converts the
two digital signals to the single three-level analog signal required by IC202.

Microphone Signals

There are two microphone source signals:
■

ITF AUX MIC AUD

■

ITF CH MIC AUD

from auxiliary or internal options connector

from control head

The biasing for electret microphones is provided by a filtered 3.0V supply
via R226 and R227. The components R209 and C202 provide the supply
filtering. The microphone inputs to IC204 (VINAUXP, VINAUXN, VINNORP, and
VINNORN balls) are differential. The negative inputs are decoupled to the
filtered 3.0V supply by C215 and C216. The positive inputs are biased to
approximately 1.5 V by R229, R232, R230 and R233. AC coupling and
DC input protection is provided by C213 and C214.
Auxiliary Audio
Input

The auxiliary audio input signal ITF AUD TAP IN is DC-coupled to the ADC
input of IC205. R241 combined with internal clamping diodes in IC205
provide DC protection for the ADC input. IC205 provides the input biasing
of approximately 1.5V.

Circuit Descriptions

TM9100 Service Manual
© Tait Electronics Limited August 2005

Auxiliary Audio
Output

The source for the auxiliary audio output signal CDC AUD TAP OUT is provided
by IC204 (RAMPDAC ball). The DAC output of IC204 is low-pass filtered to
remove high-frequency artefacts. The low-pass filter, formed by IC201
(pins 1 to 3), R219, R220, R221, R224, C206, C208 and C210, is a thirdorder Butterworth type with a cut frequency of approximately 12kHz.
The output of the low-pass filter is amplified by 6dB by a buffer amplifier,
IC201 (pins 5 to 7), and fed via R207 and R208 to drive the CDC AUD TAP
OUT interface line. The DC bias for this signal path is provided by IC204 and
is approximately 1.2V when operational. The offset at CDC AUD TAP OUT is
approximately 2.4V owing to the gain of the buffer amplifier.

TM9100 Service Manual
© Tait Electronics Limited August 2005

Circuit Descriptions

3.6

Power Supply Circuitry

Introduction

For a block diagram of the power supply circuitry, refer to Figure 3.6.
The power-supply circuitry consists of the following main sections:
■

supply protection

■

supervisory circuit

■

internal power supplies

■

control of internal power supplies

■

control of external power supply

Supply Protection

Electrical protection to the radio is provided by the clamping diode D600
and by 20A fuses (for the 50W/40W radios) and 10A fuses (for the 25W
radios) in the positive and negative leads of the power cable. This provides
protection from reverse voltages, positive transients greater than 30V, and all
negative transients. An ADC monitors the supply and is responsible for the
protection of internal devices, which have an operating voltage of less than
30V. The ADC also ensures protection if the radio operates outside its
specified voltage range of 10.8V to 16V.

Supervisory Circuit

The supervisory circuit comprises a reset and watchdog timer. The circuit
provides the reset signal PSU SYS RST to the digital section, which in turn
provides the watchdog signal DIG WD KICK required by the supervisory circuit.

Internal Power
Supplies

There are nine internal power supplies:
■

one SMPS

■

five linear regulators (+9V0, +6V0, +3V3, +3V0 AN, +2V5 CDC)

■

three switched supplies (+9V0 TX, +3V0 RX, +13V8 SW)

The SMPS is used to regulate to 3.3V from the external supply +13V8 BATT.
The four lower voltages required are then further stepped down with linear
regulators. These all take advantage of the efficiency gain of the SMPS.
The 9V regulator and the 13.8V switched supply are connected to +13V8
BATT. The two remaining switched supplies (9V and 3V) use P-channel
MOSFETs.
Control of Internal
Power Supplies

The radio can be switched on using the ON/OFF key on the control head or
by means of external signals. For the latter case hardware links are required
and there are several power-sense options; these are discussed below. Some
internal power supplies can be controlled by means of digital lines
depending on the mode in which the radio is operating.

Circuit Descriptions

TM9100 Service Manual
© Tait Electronics Limited August 2005

Figure 3.6

Block diagram of the power supply circuitry

+13V8 BATT

9V
Regulator

+9V0 TX

+9V0

9 V Tx Switch
SMPS

+3V3

3V
Regulator

Transmitter

+9V0
+3V0 AN
+6V0

Frequency
Synthesizer

+13V8 BATT
+3V0 AN
+9V0
+3V3

+2V5 CDC

2V5
Regulator

CODEC
and
Audio

Power Supply
+3V0 AN

+3V0 RX

6V0
Regulator
3 V Rx
Switch

Receiver

DIG RX EN
DIG TX EN
DIG SLP EN
+3V3
DIG PSU LATCH

IOP PWR SENSE

OR Gate

Digital
Board

IGNITION SENSE
EMERGENCY

Hardware
Links
13V8 PWR
SENSE

PSU
Supervisor

DIG WD KICK
PSU SYS RST

Debug
Connector

+3V3

Signal Types:

AGND

RF
analog

CH ON OFF
ITF IOP GPIO7
AUX GPI3
AUX GPI2
+3V3

clock
digital
asynchronous serial data
synchronous serial data

+13V8 SW

Interface

13V8 Switch
Reverse
Polarity
Protection

TM9100 Service Manual
© Tait Electronics Limited August 2005

+13V8 BATT

Circuit Descriptions

Power-Sense
Options

The radio allows the configuration of different power-sense options to
control how the radio is powered up and down:
■

battery power sense

■

auxiliary power sense (ignition sense)

■

internal-options power sense

■

no power sense

■

emergency power sense

The emergency power-sense option can be used in conjunction with any of
the other four options.
The different power-sense options have to be facilitated by hardware means,
as the software cannot act before it is powered up. The radio provides four
hardware links (LK1 to LK4) on the top-side of the main board which can
be configured to attain the power-sense option desired.
Figure 3.7 shows a block diagram of the hardware links LK1 to LK4.
Figure 3.7

Block diagram of hardware links LK1 to LK4

ON/OFF Key
13V8 BATT

LK1
13.8V Battery
Power Sense
AUX GPI3

AUX GPI2

IOP GPIO7

LK2
Auxiliary Power
Sense (Ignition)

13V8 BATT

Power-up
Circuit

LK3
Emergency
Sense
LK4
Internal Options
Power Sense

The radio can be programmed to be either on, or to return to its previous
state when the power sense signal is removed. For information on
programming the power-on mode refer to the online help of the
programming software.
The ON/OFF key can be used with any of the of the power-sense options to
turn the radio on and off.

Circuit Descriptions

TM9100 Service Manual
© Tait Electronics Limited August 2005

Table 3.1 shows the configuration of the hardware links LK1, LK2 and LK4
for the individual power-sense options. It also lists the dependence of the
power-sense options with respect to the GPI lines, which can or cannot be
used.
Table 3.1

Configuration of hardware links and GPI lines for power-sense options

Power-sense option
13.8V battery power
sense

Links
required
LK1 in

Configuration of remaining links and
use of AUX GPI3 and IOP GPIO7
LK2 in:
AUX GPI3 must be left floating.

Voltages
required
10.8V ≤ supply ≤ 16V

LK2 out:
AUX GPI3 can be used as GPIa.
auxiliary power sense

LK4 out

IOP GPIO7 can be used as GPIO.

LK2 in

LK1 in:
Input line must sink <1mA from
AUX GPI3 (which is pulled to 13.8V by a
33kΩ resistor).

AUX GPI3 ≤ 0.7V off
AUX GPI3 ≥ 2.6V high (active)
ignition-sense tolerant to
3.3V, 5V and 12V

LK1 out:
Input line must be active highb.
LK4 out
internal power sense

LK1 out
LK2 out
LK4 in

no power sense

IOP GPIO7 can be used as GPIO.
IOP GPIO7 ≤ 0.7V off
IOP GPIO7 ≥ 2.6V high
(active)
With LK4 in, the input line must be active ignition-sense tolerant to
highc.
3.3V and 5V only

AUX GPI3 can be used as GPI.

10.8V ≤ supply ≤ 16V

LK1 out
LK2 out

AUX GPI3 can be used as GPI.

LK4 out

IOP GPIO7 can be used as GPIO.

a. If LK2 is out and AUX GPIO is not used, R775 (33k) should be placed to ensure that AUX GPI3 does not float (R775
is not placed by factory default).
b. If LK1 is out and R775 is placed, AUX GPI3 should be driven low as well.
c. If LK 4 is in and R723 is placed, IOP GPIO7 should be driven low as well. (R723 is placed by factory default.)

Table 3.2 shows the configuration of ‘emergency power sense’. ‘Emergency
power sense’ can be configured with any of the above power sense options.
Table 3.2

Configuration of hardware link LK3 and AUX GPI2 for ‘emergency power sense’

External push-button
or toggle switch
required to enter
emergency mode

Links
required

Implications on AUX GPI2

Yes

LK3 in

AUX GPI2 must be connected to an
external (hidden) push-button or toggle
switch, which connects it to ground.

LK3 in

AUX GPI2 must be left floating

LK3 out

AUX GPI2 can be used as GPI.

TM9100 Service Manual
© Tait Electronics Limited August 2005

Voltages required

≤ 0.7V

active,
floating inactive

Circuit Descriptions

Battery Power
Sense

With this option, link LK1 connects +13V8 BATT of the power connector to
the power-up circuitry. With this option, when a 13.8V supply is connected
to the radio, the radio enters the programmed power-on mode. The ON/OFF
key can then be used to switch the radio on and off. This option has the
disadvantage that the radio still draws about 50mA after being switched off
using the ON/OFF key. The reason is that the radio enters the stand-by mode
and does not shut down completely.

Auxiliary Power
Sense

This option uses the digital input line AUX GPI3 of the auxiliary connector to
power the radio up and down. Link LK2 is required to connect the line to
the power-up circuitry. The line is active high; it is on when the level
exceeds 2.6V and off when the level falls below 0.7V; the line tolerates
maximum inputs equal to the radio supply voltage. When the line becomes
active, the radio enters the programmed power-on mode. The ON/OFF key
can then be used to switch the radio on and off. With the radio off and the
line active, the radio draws about 50mA. When the line becomes inactive,
the radio is shut down completely regardless of whether it was on or in
stand-by mode. With the line inactive the radio draws less than 1 mA. In a
vehicle installation this avoids flattening the battery when the ignition key is
off.

Internal-Options
Power Sense

This option is similar to the auxiliary power-sense option, except that the
IOP GPIO7 line of the internal options connector is used. Link LK4 is required
to connect the line to the power-up circuitry. This line is active high; it is
on when the level exceeds 2.6V and off when the level falls below 0.7V;
the line tolerates maximum inputs of 5V. The behavior of the ON/OFF key is
the same as with the auxiliary power-sense option.

No Power Sense

If no power-sense option is selected, the radio can only be powered up and
powered down by means of the ON/OFF key. For this option, the links LK1,
LK2 and LK4 must be removed. The advantage of this option over the
battery power-sense option is that the radio draws less than 1mA when it is
switched off.

Emergency
Power Sense

This option uses the AUX GPI2 line of the auxiliary connector. Externally, this
line is typically connected to a hidden switch. Internally, link LK3 is
required to connect the line to the power-up circuitry. The line is active low
and has an internal pull-up resistor to the external supply voltage. The line
is on when the level falls below 0.7V. When the line becomes active (when
the hidden switch is pressed for two seconds) the radio enters the emergency
mode. This mode can also be activated by making an emergency call or by
pressing a key that has been programmed appropriately. The concealed
microphone is typically fitted when the emergency power-sense option is
selected.

Circuit Descriptions

TM9100 Service Manual
© Tait Electronics Limited August 2005

Operation in
Emergency Mode

If the radio is off when the emergency mode is activated, the radio is
powered up but the display on the control head is not switched on. If the
radio is on when the mode is activated, the display is frozen. In the latter
case, if the ON/OFF key is pressed, the display is switched off but the radio
remains in the emergency mode. While in this mode the radio cycles
between transmit and receive. To exit the emergency mode, the ON/OFF key
needs to be pressed again.

Connector Power
Supply Options

Power from the radio’s primary power source is fed to the auxiliary, internal
options, control head and microphone connectors. Whether power to these
connectors is unswitched, switched or not supplied is determined by
hardware links LK5 to LK8 on the top side of the main board, as shown in
Figure 3.8 and Table 3.3.
Unswitched power means that power will always be supplied to the
connector while the primary power source is connected to the radio and is
alive. The supply to the connector is not affected by the state of the radio.
Switched power means that when the radio is off or in standby mode, the
power to the connector is switched off. The power will also be switched off
if the primary power source voltage is outside the radio’s operating range.
The switched current drawn by the control-head connector must not
exceed 1A.The switched current drawn by the internal options connector
and the auxiliary connector together must not exceed 1A.
Note

Figure 3.8

The switched output is protected. Short-circuiting the switched
power on any connector will not damage the radio. In the event
of a short circuit, the current folds back to protect the switch
device and connectors.

Connector power supply options

LK8
(R786)

LK7
(R787)

Primary
Power
Source

Power
Connector

+13V8 BATT

LK5

TM9100 Service Manual
© Tait Electronics Limited August 2005

+13V8
2

LK6

Note

Internal
Options
Connector

Auxiliary
Connector

ControlHead
Connector

Microphone
Connector

The links LK7 and LK8 have the alternative designations R787
and R786 respectively. The factory-default setting is with LK5
and LK7 inserted and LK6 and LK8 omitted

Circuit Descriptions

Table 3.3

Connector power supply options

Link state
LK5

Connector power state

LK6

LK7
(R787)

LK8
(R786)

Auxiliary

Internal
options

Control head

Microphone

out

switched

no power

out

switched

out

switched

unswitched

out

switched

unswitched

switched

out

switched

unswitched

in/out

unswitched

3.7

Interface Circuitry

Introduction

For a block diagram of the interfaces circuitry, refer to Figure 3.9.
For more on the connector pinouts, refer to “Connectors” on page 34.

Bi-directional Lines

Bi-directional lines are provided on four pins of the auxiliary connector,
(AUX GPIO4 to AUX GPIO7) one on the control-head connector (CH GPIO1), and
seven on the internal options connector (IOP GPIO1 to IOP GPIO7). Those on
the auxiliary and control-head connectors are formed by combining two
uni-directional lines. For example, the line AUX GPIO4 at pin 10 of the
auxiliary connector is formed from ITF AUX GPI4 and DIG AUX GPO4.
The circuitry is the same in all five cases and is explained below for the case
of AUX GPIO4.

Output Signals
(e.g. AUX GPIO4)

An output on the line AUX GPIO4 originates as the 3.3V signal DIG AUX GPO4
from the digital section. The signal is first inverted by Q703 (pins 3 to 5) and
the output divided down to 1.6V by R746 and R753 to drive the base of
Q703 (pins 1, 2 and 6). When the latter’s collector current is low, the base
current is a maximum and creates a small voltage drop across R761, causing
the collector emitter to saturate. As the collector current increases, the base
current decreases proportionally until the voltage across R761 reaches 1V.
At this point the base-emitter begins to turn off and the base current
diminishes rapidly. The net effect is a current-limiting action. The current
limit value is approximately 18mA (the inverse of the value of R761).
The output configuration is open-collector with a pull-up to 3.3V by
default. Pull-up options to 5V and 13.8V are also available. On AUX GPIO4
only, the optional MOSFET Q707, which has a high current drive, may be
fitted.

5-Volt Regulator

The 5V supply mentioned above is provided by a simple buffered zener
regulator formed by Q702, D721, R721 and R722. The resistor R722
limits the current to about 25mA under short-circuit conditions.

Circuit Descriptions

TM9100 Service Manual
© Tait Electronics Limited August 2005

Figure 3.9

Block diagram of the interface circuitry

+13V8 BATT
AGND

+13V8 BATT

AGND
SPK+
SPK–

Interface
Power
Supply

EMC
Filters

+3V3
+13V8 SW
AUX GPI2
AUX GPI3
CH ON OFF
ITF IOP GPIO7

EMC
Filters

ITF CH MIC AUD
CDC RX AUD
ITF RX BEEP IN
CDCAUDTAP OUT
ITF AUD TAP IN
ITF AUX MIC AUD
CDC RSSI

RX AUD

ESD and
EMC
Filters

ITF CH HOOK

PTT and
Hookswitch
Decode

ITF CH PTT

ITF CH GPI1
DIG CH GPO1

ESD and
EMC
Filters

I/O
Combine

EMC
Filters

CH ON OFF
CH RXD
CH TXD

CH GPIO1

CH SPI DI
CH SPI DO
CH SPI CLK
CH LE

RX AUD
RX BEEP IN
AUD TAP OUT
AUD TAP IN
AUX MIC AUD
RSSI
+13V8 SW

Digital
Board

ITF IOP GPIO1-6
ITF IOP GPIO7
ITF IOP RXD
DIG IOP TXD

+3V3
Clamp

+3V3 CL

Clamps
and
Pull-up
Resistors

ITF AUX RXD
DIG AUX TXD
ITF AUX GPI1
ITF AUX GPI2
ITF AUX GPI3

IOP GPIO1-6
IOP GPIO7
IOP RXD
IOP TXD
AGND
DGND

Internal
Options
Connector

AUX RXD
AUX TXD
AUX GPI1
AUX GPI2
AUX GPI3

DGND

I/O
Combine
and
Pull-up
Resistors

ITF AUX GPI4-7
DIG AUX GPO4-7

+5V

Receiver
and
Transmitter

ControlHead
Connector

CH PTT

ITF CH SPI DI
DIG CH SPI DO
DIG CH SPI CLK
DIG CH LE

Frequency
Synthesizer

SPK+
SPK–
VOL WIP DC

CH MIC AUD

ITF ON OFF
ITF CH RXD
DIG CH TXD

Debug
Connector

+13V8 BATT
+3V3
AGND
DGND

AUD ITF SPK+
AUD ITF SPKITF VOL WIP DC
AGND

CODEC
and
Audio

Power
Connector

AGND

Clamps,
ESD
Filters,
and
EMC
Filters

AGND
+13V8 SW

AUX GPIO4-7

Auxiliary
Connector

5V
Regulator
AUD TAP OUT
AUD TAP IN
AUX MIC AUD
RSSI

AGND

Signal Types:

AGND

digital

analog

asynchronous serial data

clock

synchronous serial data

TM9100 Service Manual
© Tait Electronics Limited August 2005

Circuit Descriptions

Input Signals
(e.g. AUX GPIO4)

An input signal applied to AUX GPIO4 is coupled via R757 to ITF AUX GPI4 and
fed to the digital section. As the input signal may exceed the maximum
allowed by the digital section, it is clamped by D711 and a shunt regulator.
The shunt regulator consists of Q708, R719 and R720 and begins to turn
on at approximately 2.7V. In combination with D711, the input to
ITF AUX GPI4 is therefore clamped to 3.3V nominally. The value of R757 is
made large to minimize the loading effect on the output pull-up resistors.

Input Signals
(AUX GPI1 to AUX GPI3)

Dedicated inputs are provided on three pins of the auxiliary connector
(AUX GPI1 to AUX GPI3). AUX GPI1 is a general-purpose input with strong
protection of the same type used for AUX GPIO4. AUX GPI2 is normally a
dedicated emergency input but can be made a general-purpose input like
AUX GPI1 by removing the link LK3 in the power supply area. AUX GPI3 is
normally a dedicated ignition-sense input but can be made a generalpurpose input like AUX GPI1 by removing the link LK2 in the power supply
area and fitting the 33kΩ resistor R775.

ESD Protection

On exposed inputs of the auxiliary and control-head connectors ESD
(electrostatic discharge) protection is provided by a 470pF capacitor and by
clamping diodes to ground and to 13.8V. For example, on AUX GPIO4 this
would consist of D713 and C725. The lines IOP GPIO1 to IOP GPIO7 are
intended for connection to internal digital devices and so these have
relatively light protection.

Hookswitch
Detection

Hookswitch detection is performed by Q700, R709, R706 and R712.
When the resistance to ground on the PTT line is less than 13.2kΩ, Q700
will turn on and drive the ITF CH HOOK line high; this indicates either that the
microphone is on hook or that the PTT (press-to-talk) switch is pressed.

3.8

Digital Board

Introduction

For a block diagram of the digital board, refer to Figure 3.10.
The digital board is not serviceable at level-2 and is not described in this
manual.

Circuit Descriptions

TM9100 Service Manual
© Tait Electronics Limited August 2005

Figure 3.10

Block diagram of the digital board

+3V3

Transmitter

DGND

+1V8

DIG TX INH

Serial
Flash

AGND

DIG CH SPI CLK

DIG SYN EN

DIG CH SPI DO

SYN LOCK

ITF CH SPI DI
DIG CH LE

Frequency
Synthesizer

DIG SYN TR SW

ITF CH GPI1

DIG SYN FAST

DIG CH GPO1

DIG SYN LATCH

ITF CH PTT

SYN DIG FREF

ITF CH HOOK

Interface

ITF ON OFF
ITF IOP GPIO1-7
DIG SYN SPI DO

DIG IOP TXD

DIG SYN SPI CLK

ITF IOP RXD
ITF AUX GPI1-7
DIG AUX GPO4-7

Receiver

DIG RX LE

DIG AUX TXD

RX DIG LD

ITF AUX RXD

DIG RX NB EN

DIG CH TXD
ITF CH RXD

Digital Board

DIG RX EN

DIG PSU LATCH
DIG WD KICK

FPGA

CDC2 DIG SDTO

DIG TX EN

DIG CDC2 SDTI

DIG SLP EN

DIG CDC2 CLK
DIG CDC2 LRCK
DIG DAC SPI DO

SRAM

DIG CDC ARSM
CDC DIG VSFS

DATA

CONTROL

DIG DAC LATCH

ADDRESS

DIG DAC SPI CLK

CDC DIG VSDO
PSU SYS RST

Flash
Memory

DIG CDC VSDI
CDC DIG BSOFS
CDC DIG BSDO
DIG CDC ASFS

+3V3

DIG CDC ASDI

CODEC
and
Audio

+1V8

CDC DIG ASDO
DIG AUD PA EN1

RESET
IO

DIG AUD PA EN2
DIG SYS CLK

McBSP0

DIG CDC RST

McBSP1

4
4

Power
Supply

DSP

BIRDIE

System
Clock
FPGA CLOCK

+1V5

+1V8

+1V5

1V5
Regulator

+1V8

1V8
Regulator

+3V3

PSU SYS RST

analog
clock

FPGA JTAG Signals:
JTAG FPGA TCK
JTAG FPGA TMS
FPGA JTAG TDO
JTAG FPGA TDI

DSP JTAG Signals:
JTAG DSP TCK
JTAG DSP TMS
DSP JTAG TDO
JTAG DSP TDI

JTAG DSP TRST
DSP JTAG EMU0
DSP JTAG EMU1

+3V3

digital
asynchronous serial data

DSP JTAG (x7)

FPGA JTAG (x4)

DIG RX EN

Signal Types:

Factory Connector

AGND

synchronous serial data

TM9100 Service Manual
© Tait Electronics Limited August 2005

Circuit Descriptions

3.9

Control-Head Board

Introduction

This section describes the control-head board for the control head with
graphical display.
For a block diagram of the digital circuitry, refer to Figure 3.11.
Most signals (except power on/off, speaker and microphone) to and from
the radio body are processed by a RISC processor, which is implemented on
an FPGA on the control-head board. For more information on the RISC
processor and the FPGA, refer to “Software Architecture” on page 44.

User Interface

Connectors

The control-head board includes the circuitry for the following control
elements:
■

ON/OFF

■

volume potentiometer

■

main keypad (with four functions keys, two scroll keys and
two selection keys)

■

LCD module (with backlighting and optional heating element)

■

three status LEDs

■

two function key LEDs (for function keys F1 and F4)

■

keypad backlighting LEDs

■

speaker

key

The control-head board includes the circuitry for the following connectors:
■

microphone connector (RJ45 socket)

■

control-head connector (18-way MicroMaTch socket)

■

LCD connector (for internal connection of LCD module)

■

speaker connector (2 leads)

■

soldering pads (2 leads) for concealed microphone

■

control-head options connector (for optional circuit board)

Protection circuitry is provided for the microphone connector. For pinouts
of the control-head connector and the microphone connector, refer to
“Connectors” on page 34. For more information on the control-head
options connector, please contact Tait Electronics Limited.
ON/OFF Key

When battery power (13.8V) is applied to the radio, a press of the ON/OFF key
will create an active low signal (CH ON OFF) back to the radio body to initiate
the power-on or power-off sequence. This key-press will also be detected
by the FPGA of the control head through Q611 as an active high signal.
For more information on the start-up process, refer to “Software
Architecture” on page 44.

Circuit Descriptions

TM9100 Service Manual
© Tait Electronics Limited August 2005

Block diagram of the control-head board

Contact made
when key
pressed

On/Off Key

CH ON OFF

On/Off
Keypad

CH ON OFF

+13V8

POWER ON/OFF SENSE
+1V5

+3V3

+13V8

Figure 3.11

+1V5

+3V3

Volume
Potentiometer

+3V3

VOL WIP DC
AGND

Power
Supply

WATCHDOG TRIGGER

Analog/
Digital
Converter

+3V3

RESET

TEMP SENSOR
LCD Loom

LCD

DISPLAY CONTROL

LCD
Connector

BIRDIE
BACKLIGHT

BACKLIGHT

Power
Switches

HEATER

System
Clock

HEATER
FPGA CLOCK

AGND
ENABLE

Contact made
when key
pressed

Function/
Scroll/
Selection
Keys

ConstantCurrent
Drivers

BRIGHT

SRAM

BRIGHT

DATA

Keypad
Backlighting
LEDs

BRIGHT

ADDRESS

Function
Key and
Status LEDs

CONTROL

Light Pipes

LED
Lenses

ROW

Main
Keypad

FPGA
COL

+3V3

Flash
Memory

RESET

ControlHead
Connector

+13V8

Boot
Flash
FPGA JTAG Signals:
FPGA JTAG TCK
FPGA JTAG TMS
FPGA JTAG TDO
JTAG FPGA TDI

ASYNC UART

ControlHead
Options
Connector

DEBUG
DGND
JTAG

AGND

DGND
AGND
CH SPI DO

+3V3 SENSE

+13.8 V

Signal Types:
MIC RXD

analog

MIC TXD

clock

MIC GPIO1

digital
asynchronous
serial data
synchronous
serial data

Microphone
Connector

CH RXD
CH TXD

Protection
Circuitry

CH GPIO1
CH PTT

MIC PTT

MIC RX AUD

CH RX AUD
CONTROL

MIC AUD IN
AGND

Concealed
Microphone

Microphone
Leads

Speaker Leads

Soldering
Pads

Speaker
Connector

MIC+
MIC–

Microphone
Pre-amplifier
and Audio
Switching

CH MIC AUD

Control-Head Board

SPK+

SPK–

Speaker

TM9100 Service Manual
© Tait Electronics Limited August 2005

Circuit Descriptions

Power Supply

A 3.3V regulator (U1) converts the switched 13.8V supply from the radio
body to 3.3V. A 1.5V regulator (U203) converts the 3.3V to 1.5V.
A power-sense module (U202) verifies the outputs of the voltage regulators
and—in the case of a fault—creates a power reset signal which is processed
by the FPGA.

Volume Control

The voltage level of the volume control potentiometer is converted to a
digital signal by an analog/digital converter (U601), processed by the FPGA
and transmitted to the radio body.

Main Keypad

The eight keys of the main keypad (function, scroll and selection keys) are
connected to the FPGA by an array of 3 columns and 3 rows. During idle
operation, the KEY ROW signals are driven low by the FPGA and the KEY COL
signals (pulled high by an external resistor) are monitored for activity by the
FPGA. A key-press will generate a high-to-low transition on the associated
column KEY COL signal. This, in turn, will initiate a sequence of high output
levels on the KEY ROW signals to identify which key was pressed.

LCD Module

The LCD module is connected to the control-head board via the LCD
connector. The LCD module display is controlled by a serial data link to the
FPGA. The backlighting and the optional heating element incorporated in
the LCD module are controlled by a data line each from the FPGA, which
switch two transistors on MOSFET Q102. A temperature signal from the
LCD module is converted to a digital signal by an analog/digital converter
(U601) and processed by the FPGA.

Function Key LEDs
and Status LEDs

The function key LEDs (F1 and F4) and the red, green and amber status
LEDs each are controlled by an FPGA signal and a transistor (Q604 to
Q608). The brightness level is controlled by two FPGA signals, resulting in
four intensity levels (off, low, medium and high).

Keypad
Backlighting

The keypad backlighting LEDs are controlled by two FPGA signals and two
transistors (Q2), resulting in four intensity levels (off, low, medium and
high). The keypad backlighting LEDs are arranged in two groups for the
main keypad and one group for the power button keypad, each group
consisting of three LEDs.

Speaker

The two speaker lines (SPK+ and SPK–) are connected to the speaker
connector (J104) which is joined to the control-head connector (J103)
through two ferrite beads (L105 and L106).

Microphone and
Concealed
Microphone

The audio signals from the microphone connector or the soldering pads of
the concealed microphone are routed to a switching and pre-amplifier
circuit. If a dynamic microphone is required, the pre-amplifier is engaged.
The switching logic is used to select either the standard microphone input
or the concealed microphone signal. The dynamic microphone must be
activated in the programming software.

PTT

The PTT signal from the microphone connector is connected to the FPGA
via a resistor (R25) and relayed to the radio as a digital command.

Circuit Descriptions

TM9100 Service Manual
© Tait Electronics Limited August 2005

TM9100mobiles

Chapter 2
Servicing the Radio

TM9100 Service Manual
© Tait Electronics Limited August 2005

Chapter 2 – Servicing the Radio

General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
4.1 Repair Levels and Website Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
4.2 Tools, Equipment and Spares . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
4.3 Servicing Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
4.4 Test Equipment Setup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
4.5 Replacing Board Components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
4.6 Shielding Cans and Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
4.7 SMT Repair Techniques. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
4.8 Computer-Controlled Test Mode (CCTM) . . . . . . . . . . . . . . . . . . . . . . 112
4.9 Visual and Audible Indications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

Disassembly and Reassembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .123
5.1 Removing and Mounting the Control Head . . . . . . . . . . . . . . . . . . . . . 124
5.2 Disassembling the Radio Body . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
5.3 Reassembling the Radio Body. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
5.4 Disassembling and Reassembling the Control Head . . . . . . . . . . . . . . . . 135

Servicing Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .139
6.1 Initial Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
6.2 Final Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

Power Supply Fault Finding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .153

Interface Fault Finding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .163

Frequency Synthesizer Fault Finding . . . . . . . . . . . . . . . . . . . . . . . . .169
9.1 Initial Checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
9.2 Power Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173
9.3 Phase-locked Loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
9.4 Loop Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
9.5 Receive VCO and Related Circuitry (UHF Radios) . . . . . . . . . . . . . . . 192
9.6 Transmit VCO and Related Circuitry (UHF Radios) . . . . . . . . . . . . . . . 201
9.7 VCO and Related Circuitry (VHF Radios) . . . . . . . . . . . . . . . . . . . . . . 206
9.8 Power Supply for FCL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
9.9 VCXO and TCXO Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218
9.10 Signals at TP501 and TP502 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221
9.11 VCXO and CODEC Circuitry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224

TM9100 Service Manual
© Tait Electronics Limited August 2005

10 Receiver Fault Finding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .227
10.1 Faulty Receiver Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228
10.2 Excessive Loss of Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230
10.3 Moderate or Slight Loss of Sensitivity. . . . . . . . . . . . . . . . . . . . . . . . . . . 234
10.4 Incorrect RSSI Readings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
10.5 Faulty Radio Mute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239
10.6 High Receiver Distortion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
11 Transmitter Fault Finding (50W/40W Radios) . . . . . . . . . . . . . . . . . .245
11.1 Power Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248
11.2 Transmitter RF Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257
11.3 Biasing of PA Driver and PAs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269
11.4 RF Signal Path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292
12 Transmitter Fault Finding (25W Radios). . . . . . . . . . . . . . . . . . . . . . .315
12.1 Power Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318
12.2 Transmitter RF Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324
12.3 Biasing of PA Driver and PAs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 335
12.4 RF Signal Path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 354
13 CODEC and Audio Fault Finding . . . . . . . . . . . . . . . . . . . . . . . . . . .371
13.1 Power Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 372
13.2 Faulty Speaker Audio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 375
13.3 No Speaker Audio at Auxiliary Connector . . . . . . . . . . . . . . . . . . . . . . . 382
13.4 Faulty Receiver. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 387
13.5 Faulty Modulation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 390
13.6 Faulty Modulation Using Auxiliary Connector . . . . . . . . . . . . . . . . . . . . 394
14 Fault Finding of Control Head . . . . . . . . . . . . . . . . . . . . . . . . . . . . .397
14.1 CCTM Commands. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398
14.2 Power Supply Faulty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400
14.3 LCD Display Faulty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 402
14.4 LCD Backlighting Faulty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 404
14.5 LCD Heating Faulty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 405
14.6 Function Key LEDs or Status LEDs Faulty . . . . . . . . . . . . . . . . . . . . . . . 406
14.7 Keypad Backlighting Faulty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408
14.8 On/Off Key Faulty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 410
14.9 Function, Scroll, or Selection Keys Faulty . . . . . . . . . . . . . . . . . . . . . . . 412
14.10Speaker Faulty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414
14.11Volume Control Faulty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 416
14.12PTT Faulty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 418
15 Spare Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .421

TM9100 Service Manual
© Tait Electronics Limited August 2005

General Information

Scope of Section

4.1

This section discusses the two repair levels covered by the service manual,
details concerning website access, the tools, equipment and spares
required, and the setting up of the necessary test equipment. General
servicing precautions are also given, as well as details of certain nonstandard SMT techniques required for level-2 repairs.

Repair Levels and Website Access

Repair Levels

This manual covers level-1 and level-2 repairs of TM9100 radios. Level1 repairs comprise the replacement of control-head boards, main-board
assemblies, and other parts of the radio; level-2 repairs comprise repairs
of control-head boards and, except for special items, main-board
assemblies. The special items are:
■

digital board

■

RF PAs (Q309 and Q310)

■

CODEC 1 (IC204)

■

copper plate

Replacements of the connectors and volume-control potentiometer on
the control-head board are level-1 repairs. Replacements of the
connectors on the main-board assembly, however, are level-2 repairs
because these repairs entail the disassembly of the main-board assembly.
Important

The circuit boards in the TM9100 radio are complex.
They should be serviced only by accredited service
centers (ASC). Repairs attempted without the necessary
equipment and tools or by untrained personnel might
result in permanent damage to the radio.

Accreditation of
Service Centers

Service centers that wish to achieve ASC status should contact Technical
Support. They will need to provide evidence that they meet the criteria
required for accreditation; Technical Support will supply details of these
criteria. These centers must then make available suitable staff for training
by TEL personnel, allow their service facilities to be assessed, and provide
adequate documentation of their processes. They will be accorded ASC
status and endorsed for repairs of TM9100 radios after their staff have
been trained and their facilities confirmed as suitable. Existing ASCs
need to apply for and be granted an endorsement for repairs of TM9100
radios. All ASCs with the necessary endorsements may carry out level-1
and level-2 repairs of these radios, whether under warranty or not.

Skills and Resources
for Level-1 Repairs

For level-1 repairs basic electronic repair skills are sufficient. Apart from
the standard tools and equipment of any service center, certain torque

TM9100 Service Manual
© Tait Electronics Limited August 2005

General Information

drivers are required as well as a service kit and, for diagnostic purposes,
a spare control head.
Skills and Resources
for Level-2 Repairs

For level-2 repairs expertise is required in SMT repairs of circuit boards
with a very high complexity and extreme component density. Apart
from the tools and equipment needed for level-1 repairs, the standard
SMT repair tools are required. A can-removal tool is strongly
recommended but not mandatory.

Website Access

To carry out level-1 and level-2 repairs, service centers need access to the
secured portion of the Technical Support website. There are different
access levels; those required for level-1 and level-2 repairs are:
■

level-1 repairs: associate access

■

level-2 repairs: ASC and Tait-only access

Log-in passwords are needed for associate and Tait-only access; Technical
Support supplies service centers with the necessary log-in information.
(The unsecured portion of the Technical Support website is accessible to
the general public. This type of access is called public access, and no login password is required.)
Items Available
on Website

Table 4.1

The information available at the different access levels is summarized in
Table 4.1. The technical notes mentioned are of different types.
Associate technical notes relate to the repair of the radio but not the
downloading of firmware; Tait-only technical notes relate to the
firmware. The PCB information packs are discussed in more detail
below.

Items relating to TM9100 radios that are available on the Technical Support website

Item
User’s guide
Installation guide
Public technical notes
Product safety and compliance information
Product release notes
Specifications
Calibration software
Programming software
Programming user manuals
Fitting instructions
Service manual
Associate technical notes
Software release information
Firmware
Tait-only technical notes
PCB information

General Information

Public
access

Associate
access

ASC
access

Tait-only
access

•
•
•
•

•
•
•
•
•
•
•
•

•
•

•
•
•
•

•

TM9100 Service Manual
© Tait Electronics Limited August 2005

PCB Information

PCB information for a particular circuit board consists of the relevant
BOMs, grid reference indexes, PCB layouts, and circuit diagrams.
(The grid reference indexes give the locations of components on the
PCB layouts and circuit diagrams.) PCB information is compiled
whenever there is a major change in the layout of the board. All PCB
informations are published on the Technical Support website.

Tait FOCUS Database

An additional source of information to service centers is the Tait
FOCUS call-logging database. (This is accessible on the Technical
Support website also.) All Customer-related technical issues regarding
the radios are recorded on this database. These issues may be raised by
both Customers and service centers. Technical Support resolves the
issues and informs the Customer or service center concerned of the
outcome. All issues and their solutions are available for review by all
service centers.

TM9100 Service Manual
© Tait Electronics Limited August 2005

General Information

4.2

Tools, Equipment and Spares

Torque-drivers

For level-1 and level-2 repairs, excluding SMT repairs of the circuit
boards, the following torque-drivers are required.
■

For level-1 repairs Torx T6, Torx T10, and Torx T20 driver bits are
necessary.

■

For level-1 repairs, 3/16 inch and 14mm long-reach sockets are
required.

Refer to the illustrations in “Reassembling the Radio Body” on
page 131 for the corresponding torque values.
Tools for SMT Repairs

In general only the standard tools for SMT work are required for level-2
repairs of the circuit boards. In addition, a can-removal tool is
recommended but if none is available, a hot-air tool may be used instead.
However, it should be noted that a hot-air tool affords little control. Even
in skilled hands, use of a hot-air tool to remove cans will result in rapid
uncontrolled rises in the temperature of components under the can being
removed as well as under any adjacent cans. The circuit board might
suffer damage as a result.

Test Equipment

The following test equipment is required for servicing the radio:
■

test PC (with programming and calibration applications loaded)

■

RF communications test set (audio bandwidth of at least 10kHz)

■

oscilloscope

■

digital current meter (capable of measuring up to 20A)

■

multimeter

■

DC power supply (capable of 13.8V and 20A for the 50W/40W
radios, and 10A for the 25W radios)

■

spare control head

■

service kit

Separate instruments may be used in place of the RF communications
test set. These are an RF signal generator, audio signal generator, audio
analyzer, RF power meter, and modulation meter.

100

General Information

TM9100 Service Manual
© Tait Electronics Limited August 2005

The service kit contains all the items needed for connecting the radio to
the test equipment. The setting up of the equipment is described in
“Test Equipment Setup” on page 105. The service kit also includes a
service CD and a folder with the necessary service documentation,
including this manual. The CD contains the programming application,
calibration application, and soft-copies of the service and related
documentation. The contents of the service kit are listed in Table 4.2.
Note that the TMAA20-04 cable listed is required only if the test PC is
to be connected directly to the radio for programming purposes.

Service Kit

Note

Table 4.2

The characters xx below stand for the issue number of the
manual. Only the latest issue of each manual will normally be
available for ordering.

Contents of service kit (TMAA24-00)

Product code

Item

TMAA21-01

Cable (DB15 socket to RJ45 plug plus speaker connector)

TMAA23-02

Cable (50W/40W power connector to banana plugs plus speaker connector)

TMAA20-03

Cable (25W power connector to banana plugs plus speaker connector)

TMAA20-04

Cable (RJ12 socket to RJ45 plug)

TPA-SV-006

Programming cable (DB9 socket to RJ12 plug)

T950-001

Cable (USB1.1 to serial DB9 pin)

TOPA-SV-024

Test unit

MMA-00017-xx

Service manual

MMA-00026-xx

PCB information

TMAA24-01

Service CD

The following components are included in the service kit, but are used for the TP9100 portable radios only:
TOPA-SV-006

RF cable

TPA-SV-005

Battery eliminator (power supply adaptor)

TPA-SV-007

Programming cable (RJ12 socket to TP9100)

TPA-SV-011

Calibration cable (DB15 socket to TP9100)

TM9100 Service Manual
© Tait Electronics Limited August 2005

General Information

101

4.3

Servicing Precautions

Introduction

This section discusses the precautions that need to be taken when
servicing the radios. These precautions fall into the following categories:
■

mechanical issues

■

compliance issues

■

anti-static precautions

■

transmitter issues

Service technicians should familiarize themselves with these precautions
before attempting repairs of the radios.
Use of Torque-drivers

Apply the correct torque when using a torque-driver to tighten a screw
or nut in the radio. Under-torquing can cause problems with
microphonics and heat transfer. Over-torquing can damage the radio.
The illustrations in “Disassembly and Reassembly” on page 123 show
the correct torque values for the different screws and nuts.

Non-scratch Bench Tops

Use workbenches with non-scratch bench tops so that the mechanical
parts of the radio are not damaged during disassembly and re-assembly.
(The workbench must also satisfy the anti-static requirements specified
below.) In addition, use a clear area of the bench when disassembling and
re-assembling the radio.
Note

Sealing of Radio

The radio is designed to satisfy the applicable compliance regulations. Do not make modifications or changes to the radio
not expressly approved by TEL. Failure to do so could invalidate compliance requirements and void the Customer’s authority to operate the radio.

To maintain the sealing of the radio to IP54 standards, ensure that all
bungs and seals are fitted after servicing the radio. These are for the
auxiliary, RF, external options, and programming connectors:
■

bung for auxiliary connector

■

rubber seal for RF connector

■

bung for aperture for options connector (connector not fitted)

■

cover seal for options connector (connector fitted)

In addition, ensure that the grommet sealing the aperture to the
microphone connector of the control head is properly fitted.

102

General Information

TM9100 Service Manual
© Tait Electronics Limited August 2005

ESD Precautions

Important

This equipment contains devices which are susceptible
to damage from static discharges. You must handle these
devices carefully and according to the procedures
described in the manufacturers’ data books.

Purchase an antistatic bench kit from a reputable manufacturer and install
and test it according to the manufacturer’s instructions. Figure 4.1 shows
a typical antistatic bench set-up.
You can obtain further information on antistatic precautions and the
dangers of electrostatic discharge (ESD) from standards such as ESD
S4.1-1997 (revised) or EN 100015-4 1994. The Electrostatic Discharge
Association website is http://www.esda.org/.
Figure 4.1

Typical antistatic bench set-up
conductive wrist strap

dissipative rubber
bench mat

to building ground or
mains ground via
1MΩ series resistor

Storage and Transport
of Items

Always observe anti-static precautions when storing, shipping or
carrying the circuit boards and their components. Use anti-static bags for
circuit boards and anti-static bags or tubes for components that are to be
stored or shipped. Use anti-static bags or trays for carrying circuit boards,
and foil or anti-static bags, trays, or tubes for carrying components.

Anti-static
Workbenches

Use an anti-static workbench installed and tested according to the
manufacturer’s instructions. A typical installation is shown in Figure 4.1.
These benches have a dissipative rubber bench top, a conductive wrist
strap, and a connection to the building earth. The material of the bench
top must satisfy not only anti-static requirements but also the non-scratch
requirements mentioned above.

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Transmitter Issues

The following issues relate to the operation of the transmitter:
■

RF and thermal burns

■

antenna loading

■

test transmissions

■

accidental transmissions

■

distress beacons

The precautions required in each case are given below.
Caution

Avoid thermal burns. Do not touch the cooling
fins or underside of the radio body when the
transmitter is or has been operating. Avoid RF
burns. Do not touch the antenna while the transmitter is operating.

Important

The radio has been designed to operate with a 50Ω
termination impedance. Do not operate the transmitter
without a suitable load. Failure to do so might result in
damage to the power output stage of the transmitter.

Important

While servicing the main board, avoid overheating the
radio during test transmissions. The following is good
practice: Secure the main-board assembly in the chassis
with the two external screws and one of the internal
screws. The heat-transfer block must be secured to the
main board. The lid of the radio body may be left off.
After completing any measurement or test requiring
activation of the transmitter, immediately return the
radio to the receive mode.

Important

Under certain circumstances the microprocessor can key
on the transmitter. Ensure that all instruments are
protected at all times from such accidental transmissions.

Note

104

General Information

The frequency ranges 156.8MHz±375kHz,
243MHz±5kHz, and 406.0 to 406.1MHz are reserved worldwide for use by distress beacons. Do not program transmitters
to operate in any of these frequency bands.

TM9100 Service Manual
© Tait Electronics Limited August 2005

4.4

Test Equipment Setup

Introduction

This section covers the setting up of the test equipment for servicing the
radios, as well as related aspects:
■

setting up of test equipment, including test unit

■

basic programming and calibration tasks

■

invoking CCTM (computer-controlled test mode)

■

summary tables of CCTM commands and error codes

■

visual and audible indications provided by radio

The last-named aspect applies to control heads with UI, and concerns
the STATUS LEDs and LCD screen, and the various alerts and confidence
tones emitted from the speaker.
Connect Equipment

Connect the test equipment to the radio as shown in Figure 4.2. Use the
test unit, cables and adaptor of the service kit. Refer to “Tools,
Equipment and Spares” on page 100 for details of the test equipment and
service kit. The test unit is described in “TOPA-SV-024 Test Unit” on
page 477.
For testing receive and transmit functions respectively, the switches of the
test unit must be set as described below. (When programming or
calibrating radios the switches have no effect, although it is good practice
to set the MODE switch to “RX”.)

Settings for
Receive Tests

For receive tests set the switches on the test unit as follows:
■

HOOK

switch

: “OFF HOOK”

■

MODE

switch

: “RX”

■

AUDIO IN

■

AUDIO OUT

switch : “OFF”
switch: “SPEAKER” or “LOAD”

In the last-named case, with the switch in the “SPEAKER” position, the
received audio is output from the test unit’s speaker. In the “LOAD”
position a 16Ω load is switched into the circuit in place of the test unit’s
speaker. Note, however, that the AUDIO OUT switch has no effect on the
radio’s speaker.
Settings for
Transmit Tests

For transmit tests set the switches on the test unit as follows:
■

HOOK

switch

: “OFF HOOK”

■

MODE

switch

: “RX” initially

■

AUDIO IN

■

AUDIO OUT

switch : “MIC AUDIO”
switch: (immaterial)

When ready to transmit, set the MODE switch to the “TX/PTT” position.
This switch functions in the same way as the PTT switch on the
microphone.

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General Information

105

Install the programming and calibration applications on the test PC.
These applications are included on the service CD supplied with the
service kit.

Service CD

Figure 4.2

Test setup

Test PC

serial port
(DB9)
RF comms set

T950-001
USB1.1 to serial
DB9 adapter
(optional)

TOPA-SV-024

computer
connector
(RJ12)

TPA-SV-006
cable

RF in/out
(N-type)

transmit audio
connector (BNC)

AUDIO
OUT
(BNC)

AUDIO
IN HI
(BNC)

audio
monitor
out (BNC)

receive audio /
SINAD connector
(BNC)
radio connector
(DB15)
speaker
connector

Oscilloscope
TMAA21-01 cable

microphone
connector (RJ45)

AC input
(BNC)

TM9100 radio

power
connector

auxiliary
connector
(DB15)

TMAA23-02 cable
(50W/40W radios)
TMAA20-03 cable
(25W radios)

RF connector
(mini UHF or
BNC)

DC power supply

banana plugs

106

General Information

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4.5

Replacing Board Components
This section describes the procedure for obtaining the correct
replacement for any faulty component on the boards.
■

identify version of PCB information applicable to board

■

identify replacement component in BOM of PCB information

■

consult technical notes

■

obtain replacement component

The technical notes will indicate whether there have been any changes
affecting the component in question.
Identify
PCB Information

Identify the IPN of the PCB and compare the issue number with that in
the PCB information supplied with the service documentation.
Note

The IPN is the ten-digit number printed at one corner of the
board. The last two digits in the IPN represent the issue number of the PCB.

If the issue numbers match, consult the BOM as described below. If the
issue number indicates that the board is either an earlier or a later version,
obtain the PCB information for the board under repair from the
Technical Support website (support.taitworld.com).
Tip

Print and store a copy of every PCB information published on
the Technical Support website.

Identify Replacement
Component

After locating the correct PCB information for the board, consult the
BOM for the board. Identify the component in question in the BOM.
Note, however, that a new PCB information is published only whenever
there is a major change in the design of the board. A major change
normally involves a change in the layout of the PCB, which requires that
the issue number in the IPN be incremented. Any minor changes
following a major change (and preceding the next major change)
normally involve only changes in the components on the board. Such
minor changes might affect the component in question. To determine if
this is the case, consult any technical notes that might apply to the board
as described below.

Consult Technical Notes

A technical note about each major change is published on the Technical
Support website (support.taitworld.com). Technical notes giving details
of any intervening minor but important changes are also published. It is
advisable to print and store a copy of every technical note published.

Obtain Replacement
Component

Determine if the required replacement component is included in one of
the spares kits. (Check with TEL regarding the availability of the kit.)
If the required component is not included in a kit, order the component
from a CSO or, in the case of a CSO, from TEL. Always ensure that the
replacement component has the identical specification to that given in
the BOM. It is particularly important for the tolerances to be the same.

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General Information

107

4.6

Shielding Cans and Connectors
The shielding cans on the top- and bottom-side of the main-board
assembly are identified in Figure 4.3 and Figure 4.4. The figures also
show the locations of the connectors on the board.

Figure 4.3

Shielding cans and connectors (top side of main-board assembly)

PIN TOP

LPF TOP

DIRC TOP
FE TOP

PAF TOP
VCO TOP
(UHF ONLY)

IF TOP

SYN TOP

PAD TOP

FCL TOP
CDC TOP

PL101
FACTORY
CONNECTOR

DIGITAL BOARD

108

General Information

SK102
INTERNAL-OPTIONS
CONNECTOR

TM9100 Service Manual
© Tait Electronics Limited August 2005

Figure 4.4

Shielding cans and connectors (bottom side of main-board assembly)

SK103 RF CONNECTOR
NB BOT
(VHF ONLY)

COPPER PLATE
SK100
CONTROLHEAD
CONNECTOR

VCO BOT

LO2 BOT

SYN BOT

VCXO BOT
CDC BOT
PL100
POWER
CONNECTOR

DIGITAL BOARD

SK101
AUXILIARY
CONNECTOR

Can Removal
and Installation

Cans are best removed and installed using a can-removal tool. If this tool
is available, technicians should refer to the documentation supplied with
the tool for the correct procedures. If the tool is not available, a hot-air
tool may be used instead. However, technicians require training in the
best techniques to employ in the absence of a can-removal tool. Such
training is part of the accreditation process for service centers.

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General Information

109

It is good practice to discard any can that has been removed and replace
it with a spare can. If this is not done, special precautions are needed
when re-installing the original can. These precautions are discussed as
part of the training for accreditation.

Spare Cans

4.7

SMT Repair Techniques

Standard Procedures

Service centers carrying out level-2 repairs are expected to be familiar
with the standard techniques for the replacement of SMT components.
However, certain components on the main board require non-standard
techniques and these are discussed below. Another issue of concern is the
procedure for removing and installing cans. A discussion of the issue
concludes this section.

Non-standard
Procedures

Do not use the standard SMT repair techniques when replacing the
capacitors C548 and C565 and the inductors L601 and L602.
The standard techniques tend to produce excessive heat, which will
damage these components. Do not use a hot-air tool or heat gun. Instead
use solder paste and a standard soldering iron with an iron tip with a
specified temperature of 600°F (315°C). The capacitors are part of the
frequency-synthesizer circuitry under the SYN TOP can. The inductors are
part of the SMPS of the power-supply circuitry on the bottom-side of
the board. Figure 4.5 on page 111 shows the locations of the
components.

110

General Information

TM9100 Service Manual
© Tait Electronics Limited August 2005

Figure 4.5

Locations of the capacitors C548 and C565 and the inductors L601 and L602

top side
(VHF board. UHF board similar)
Note that other components may be
fitted for C548 (such as C5085 and
C5086 for UHF radios)

bottom side
(UHF board. VHF board similar)

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111

4.8

Computer-Controlled Test Mode (CCTM)
The servicing procedures require a radio to be placed in the computercontrolled test mode. In this mode CCTM commands can be entered at
the test PC. These commands are then relayed via the test unit to the
radio. Certain CCTM commands cause the radio to carry out particular
functions; others read particular settings and parameter values in the
radio. The CCTM commands of use in servicing radios are listed in
Table 4.3 to Table 4.7, grouped according to category.

Terminal Program
for CCTM

Use the calibration application to place the radio in CCTM. To do this,
run the calibration application, select Tools > CCTM, and click the CCTM
Mode button. For more information, refer to the online help of the
calibration application.
You can also use the HyperTerminal utility which is supplied with
Microsoft Windows. As a preliminary, first select the settings for the
communications port as follows:

Invoking CCTM

112

Open the terminal program. (In the case of HyperTerminal, click
Start > Programs > Accessories > Communications > HyperTerminal.)

In the terminal program first select the COM port to which the
radio is connected. Then select the following settings for the port:
■

bits per second : 19 200

■

data bits

■

parity

: none

■

stop bits

■

flow control

: none

Click the OK button (or equivalent).

Save the file with the port settings under a suitable name.
For subsequent sessions requiring the terminal program, open this
file.

Using the terminal program, place the radio in CCTM as follows:
1.

Enter the character ^ to reset the radio.

As soon as the radio is reset, the letter v is displayed. (If an
uppercase letter V appears, this implies a fault.)

Immediately the letter v is displayed, enter the character%.
(The character% must be entered within half a second of the letter
v appearing.)

If the character% is accepted, the character – is displayed in
response, and the message Test Mode appears on the radio display.

General Information

TM9100 Service Manual
© Tait Electronics Limited August 2005

This implies that the radio has entered CCTM. If the attempt
fails, repeat Steps 1 to 3.
Table 4.3

CCTM commands in the audio category
Usage

Command
Entry at keyboard

Response on screen

Audio category
20 – Mute received audio
Forces muting of the received
audio signal

None

21 – Unmute received audio
Forces unmuting of the received
audio signal

None

22 – Mute microphone
Mutes transmit modulation
(effectively mutes microphone
audio)

None

23 – Unmute microphone
Unmutes transmit modulation
(effectively unmutes microphone
audio)

None

74 – Audio PA
Controls the state of the audio PA
(and hence enables or disables the
speaker)

74 x
where x is the required state
(0=stand-by, 1=on, 2=mute)

None

110 – Audio volume
Sets the level of the audio volume

110 x
where x defines the required level
(any integer from 0 to 255)

None

138 – Select microphone
Selects the microphone required

138 x
None
where x is the required microphone
(0=control-head microphone;
1=auxiliary microphone)

323 – Audio tap in
323 x y
None
Generates the audio tone AUD TAP IN where x specifies the tap point
at the specified tap point
(r2, r5, t1 or t5) and y the tap type
(A=bypass in, B=combine, E=splice)
(the default is A when y is omitted)
324 – Audio tap out
Outputs the audio signal at the
specified tap point to AUD TAP OUT

TM9100 Service Manual
© Tait Electronics Limited August 2005

324 x y
None
where x specifies the tap point
(r1, r2, r3, r4, r5, t1, t2, t3 or t7)
and y the tap type
(C=bypass out, D=split, E=splice)
(the default is D when y is omitted)

General Information

113

Table 4.4

CCTM commands in the radio-information, radio-control and system categories
Usage

Command
Entry at keyboard

Response on screen

Radio-information category
94 – Radio serial number
Reads the serial number of the
radio

x
where x is the serial number
(an eight-digit number)

96 – Firmware version
Reads the version number of the
radio firmware

QMA1F_x_y
where x is a three-character
identifier and y is an eight-digit
version number

97 – Boot-code version
Reads the version number of the
boot code

QMA1B_x_y
where x is a three-character
identifier and y is an eight-digit
version number

98 – FPGA version
Reads the version number of the
FPGA

QMA1G_x_y
where x is a three-character
identifier and y is an eight-digit
version number

133 – Hardware version
Reads the product code of the
radio body and the hardware
version number

133

x
y
where x is the product code
and y is the version number
(a four-digit number)

134 – FLASH serial number
Reads the serial number of the
FLASH memory

134

x
where x is the serial number
(a 16-digit hexadecimal number)

400 x (alternatively *x )
where x is a valid channel number

None

46 – Supply voltage
Reads the supply voltage

x
where x is the supply voltage in
millivolts

203 – Clear system error
Clears the last recorded system
error

203

None

204 – Read system error
Reads the last recorded system
error and the associated data

204

SysErr: x
y
where x is the error number and
y represents the associated data

205 – Erase persistent data
Effectively resets the calibration
parameters to their default values

205

None

Radio-control category
400 – Select channel
Changes the current channel to
that specified
System category

114

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TM9100 Service Manual
© Tait Electronics Limited August 2005

Table 4.5

CCTM commands in the frequency-synthesizer and receiver categories
Usage

Command
Entry at keyboard

Response on screen

Frequency-synthesizer category
72 – Lock status
72
Reads the lock status of the RF PLL,
FCL and LO2 respectively

xyz
where x is the RF PLL, y the FCL,
and z the LO2 lock status
(0=not in lock, 1=in lock)

101 – Radio frequencies
Sets the transmit and receive
frequencies to specified values

101 x y 0
where x is the transmit and y the
receive frequency in hertz
(any integer from 50 000 000 to
1000 000 000)

None

301 – Calibrate VCXO
Calibrates the VCXO of the FCL

301 0 10

Four KVCXO control sensitivity
values, followed by message with
results of calibration attempt

302 – Calibrate VCO(s)
Calibrates the VCO(s) of the
frequency synthesizer

302 0 10

Eight KVCO control sensitivity
values, followed by message with
results of calibration attempt

334 – Synthesizer power
334 x
Switches the frequency synthesizer where x is the required state
on or off via the DIG SYN EN line
(0=off, 1=on)

None

335 x
335 – Synthesizer switch
where x is the required state
Switches the transmit-receive
switch of the frequency synthesizer (0=off, 1=on)
on or off via the DIG SYN TR SW line

None

389 – Synthesizer mode
Sets the mode of the frequency
synthesizer to fast or slow

389 x
where x is the required mode
(0=slow, 1=fast)

None

32 – Receive mode
Sets the radio in the receive mode

None

63 – RSSI level
Reads the averaged RSSI level

x
where x is the averaged level in
multiples of 0.1 dBm

Receiver category

376 – Front-end tuning
376 (to read voltage)
Sets or reads the tuning voltage for
the front-end circuitry of the
receiver
376 x (to set voltage)
where x is the front-end tuning
voltage in millivolts
(any integer from 0 to 3000)

x
where x is the front-end tuning
voltage in millivolts

378 – Receiver output level
Reads the signal power at the
output of the channel filter
(the square of the amplitude)

x
where x is the signal power

TM9100 Service Manual
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378

None

General Information

115

Table 4.6

CCTM commands in the transmitter category (part 1)
Usage

Command
Entry at keyboard

Response on screen

Transmitter category
33 – Transmit mode
33
Sets the radio in the transmit mode

None

47 – Temperature
Reads the temperature in the
vicinity of the PAs

x
y
where x is the temperature in
degrees celsius, and y is the
corresponding voltage in millivolts
(a value from 0 to 1200 mV)

114 – Transmitter power
114 (to read value)
Sets or reads the transmitter power
setting (compare command 326)

x
where x is the current power
setting (an integer from 0 to 1023)

114 x (to set value)
None
where x is the required power
setting (an integer from 0 to 1023)
304 – Driver bias
Sets or reads the clamp current at
the gate of the PA driver

304 (to read value)

x
where x is the DAC value of the
clamp current (an integer from 0 to
255)

304 x (to set value)
where x is the required DAC value
of the clamp current
(an integer from 0 to 255)

None

318 – Forward power
Reads the forward-power level

318

x
where x is the voltage in millivolts
corresponding to the power level
(a value from 0 to 1100 mV)

319 – Reverse power
Reads the reverse-power level

319

x
where x is the voltage in millivolts
corresponding to the power level
(a value from 0 to 1100 mV)

326 – Transmitter power
Sets the power level of the
transmitter

326 x
where x specifies the level
(0=off, 1=very low, 2=low,
3=medium, 4=high, 5=maximum)

None

116

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Table 4.7

CCTM commands in the transmitter category (part 2)
Usage

Command
Entry at keyboard

Response on screen

Transmitter category
331 – Final bias 1
Sets or reads the bias voltage for
the first PA

332 – Final bias 2
Sets or reads the bias voltage for
the second PA

TM9100 Service Manual
© Tait Electronics Limited August 2005

331 (to read value)

x
where x is the DAC value of the
bias voltage (an integer from 0 to
255)

331 x (to set value)
where x is the DAC value of the
required bias voltage
(any integer from 0 to 255)

None

332 (to read value)

x
where x is the DAC value of the
bias voltage (an integer from 0 to
255)

332 x (to set value)
where x is the DAC value of the
required bias voltage
(any integer from 0 to 255)

None

General Information

117

Table 4.8

CCTM commands for the control-head
Usage

Command
Entry at keyboard
1000 – Switch all LEDs
Switches all the function-key and
STATUS LEDs on or off

1000 x
where x is the required state
(0=off, 1=on)

1001 – Switch selected LED
1001 x y
Switches a selected function-key or where x identifies the LED
STATUS LED on or off
(0=F1, 1=F4, 2=yellow, 3=green,
4=red) and y is the state
(0=off, 1=on)

Response on screen
None

None

1002 – LED intensity
Sets the LED intensity

1002 x
None
where x is the intensity level
(0=off, 1=low, 2=medium, 3=high)

1003 – Keypad back-lighting
Activates the keypad back-lighting
at a specified intensity

1003 x
None
where x is the intensity level
(0=off, 1=low, 2=medium, 3=high)

1004 – LCD back-lighting
Activates the LCD back-lighting at
a specified intensity

1004 x
None
where x is the intensity level
(0=off, 1=low, 2=medium, 3=high)

1005 – Display contrast
1005 x
Sets the contrast of the display to a where x is the contrast level
specified level
(any integer from 0 to 15)

None

1006 – Display elements
Switches all the elements of the
display on or off

1006 x
where x is the required state
(0=off, 1=on)

None

1007 – LCD temperature sensor
Reads the output of the LCD
temperature sensor

1007

x
where x corresponds to the
temperature reading
(an integer between 00 and FF)

1008 – LCD heating
1008 x
Switches the LCD heating on or off where x is the required state
(0=off, 1=on)

None

1009 – Key press
Switches on or off the facility for
detecting if any key is pressed or
released

1009 x
where x is the required state
(0=off, 1=on)

x
where x is the serial output from
the detection facility

1010 – Volume control
Reads the setting of the volumecontrol potentiometer

1010

x
where x is the potentiometer
setting
(an integer between 00 and FF)

1011 – Microphone source
Selects the microphone input
source

1011 x
where x is the required source
(0=microphone connector,
1=concealed microphone)

None

118

General Information

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Table 4.9

CCTM commands of the remote control-head kit

CCTM command

Entry at keyboard

Response on screen

1012 – Remote kit
turns the audio amplifier on and off

1012 0 = off
1012 1 = on

none

1013 – Mute audio amplifier
mutes and unmutes the audio amplifier

1012 0 = mute
1012 1 =unmute

none

1014 – Digital potentiometer
reads the digital potentiometer

1014

value between 0 and
255

1017 – Audio amplifier gain
sets the audio amplifier gain (4 levels)

1017 x
where x is the gain (0 to 3)

none

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General Information

119

CCTM Error Codes

Table 4.10
Error code

Once the radio is in CCTM, the CCTM commands may be entered as
shown in Table 4.3 to Table 4.7. Depending on the command, a
response might or might not be displayed. If an error occurs, an error
code will be displayed. Possible error codes are listed in Table 4.10.

CCTM error codes
Description

C01

An invalid CCTM command has been received. Enter a valid CCTM command.

C02

A valid CCTM command with invalid parameters has been received. Re-enter the CCTM
command with valid parameters.

C03

A valid CCTM command has been received but cannot be processed at this time. Enter the
CCTM command again. If the error persists, power the radio down and up again, and re-enter
the CCTM command.

C04

An error occurred on entry into CCTM. Power the radio down and up again, and place the
radio in CCTM again.

C05

The radio has not responded within the specified time. Re-enter the CCTM command.

X04

The DSP is not responding. Check the DSP pin connections. If the error persists, replace the
DSP.

X05

The version of the DSP is incompatible with the version of the radio firmware. Replace the DSP
with a later version.

X06

The internal configuration of the MCU is incorrect. Adjust the configuration.

X31

There is an error in the checksum for the model configuration.

X32

There is an error in the checksum for the radio’s database.

X35

The radio temperature is above the T1 threshold and a reduction in the transmit power is
impending. To avoid damaging the radio, stop transmitting until the radio has cooled down
sufficiently.

X36

The radio temperature is above the T2 threshold and the inhibiting of transmissions is
imminent.

X37

The supply voltage is less than the V1 threshold.

X38

The supply voltage is less than the V2 threshold and the radio has powered itself down.
The radio will not respond to the reset command character ^.

120

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© Tait Electronics Limited August 2005

4.9

Visual and Audible Indications
Visual and audible indicators give information about the state of the
radio. Visual indications are provided by the STATUS LEDs, function-key
LEDs, and LCD display. The information conveyed by the STATUS LEDs
is listed in Table 4.11. The behavior of the function-key LEDs depends
on the way the function keys are programmed. The LCD display
normally displays channel and user information, or error messages. For
more information on the LCD display during normal operation, refer to
the user’s guide. The error messages are listed in Table 6.1 on page 144.
Audible indications are provided in the form of different tones emitted
from the speaker. The information conveyed by the tones is given in
Table 4.12 on page 122.

Table 4.11
LED color
Red

Green

Amber

Visual indications provided by the STATUS LEDs
LED name
Transmit

Receive and
monitor

Scanning

Indications

Meanings

LED is on

The radio is transmitting

LED flashes

(1) The transmit timer is about to expire
(2) The radio has been stunned

LED is on

There is activity on the current channel, although it might
not be audible

LED flashes

(1) The radio has received a call with valid special signaling
(2) The monitor has been activated
(3) The squelch override has been activated

LED is on

The radio is scanning a group of channels for activity

LED flashes

The radio has detected activity on a certain channel and
scanning has halted on this channel

TM9100 Service Manual
© Tait Electronics Limited August 2005

General Information

121

Table 4.12

Audible indications

Type of tone
One short beep

Meanings
(1) After power-up — Radio is locked; PIN is required
(2) On power-down — Radio is off
(3) On pressing key — Key-press is valid
(4) On pressing function key — Function has been initiated

One short low-pitched beep On pressing function key again — Function has been terminated
One short high-pitched beep While powered up — Radio has been stunned
One long low-pitched beep

(1) On pressing key — Key-press is invalid
(2) On entry of PIN — PIN is invalid
(3) On pressing PTT switch — Transmission is inhibited

Two short beeps

(1) On power-up — Radio is ready to use
(2) On entry of PIN — PIN has been accepted and radio is ready to use
(3) After radio has been stunned — Radio has been revived and is ready to use

Two low-pitched beeps

While powered up — Temperature of radio is high

Two high-pitched beeps

While powered up — Temperature of radio is very high and all transmissions
will be at low power; if temperature rises further, transmissions will be inhibited

Three short beeps

While powered up — Previously busy channel is now free

Three beeps

During transmission — Transmit time-out is imminent; transmission will be
terminated in 10 seconds

Warble

While powered up — Frequency synthesizer is out of lock on current channel;
LCD will usually display Out of Lock.

Continuous low-pitched
tone

While powered up — System error has occurred and radio might be inoperable;
LCD usually displays E1 or E2.

122

General Information

TM9100 Service Manual
© Tait Electronics Limited August 2005

Disassembly and Reassembly
This section describes how to:

General

■

remove and mount the control head

■

disassemble and reassemble the radio body

■

disassemble and reassemble the control head

Important

Before disassembling the radio, disconnect the radio from
any test equipment or power supply.

Disassemble only as much as necessary to replace the defective parts.
Inspect all disassembled parts for damage and replace them, if necessary.
Observe the torque settings indicated in the relevant figures.
For information on spare parts, refer to “Spare Parts” on page 421.

TM9100 Service Manual
© Tait Electronics Limited August 2005

Disassembly and Reassembly

123

5.1

Removing and Mounting the Control Head
Important

Removing the
Control Head

Before removing the control head, disconnect the radio
from any test equipment or power supply.

Note which way up the control head is attached to the radio body in
order to return the radio to the customer in its original configuration.

On the underside of the radio body, two lever points are indicated on
the radio body by a dot-dash-dot pattern (
).
The lever point is between the control-head seal and the plastic of the
control head.

Figure 5.1

Disconnecting the control head from the radio body
control head
lever point

control-head
seal
indication of
lever point

Important

Mounting the
Control Head

124

When inserting the flat-bladed screwdriver, take care not to
damage the control-head seal.

At either of the lever points, insert a 3/16 inch (5mm) flat-bladed
screwdriver between the control head and the control-head seal.

Use the screwdriver to lift the edge of the control head up and off the
clip, then repeat in the other position. The control head can now be
removed.

Disconnect the control-head loom.

Inspect the control-head seal for damage, and replace if necessary.

Plug the control-head loom onto the control-head connector.

Insert the bottom edge of the control head onto the two clips in the
front of the radio body, then snap into place.

Disassembly and Reassembly

TM9100 Service Manual
© Tait Electronics Limited August 2005

5.2

Disassembling the Radio Body
Disassemble only as much as necessary to replace the defective parts.
For reassembly instructions, refer to “Reassembling the Radio Body” on
page 131.

Removing the Cover

At the upper edge of the lower screw bosses on both sides of the radio
body, insert a 1/8 inch (3mm) flat-bladed screwdriver.

Push the screwdriver under the cover towards the upper screw boss to
release the cover from the upper screw boss.

Remove the cover.

Figure 5.2

Removing the cover

upper
screw boss
insertion
point

lower
screw boss
cover

TM9100 Service Manual
© Tait Electronics Limited August 2005

Disassembly and Reassembly

125

Opening the
Radio Body

The circled numbers in this section refer to the items in Figure 5.3 on
page 127.
1.

Use a Torx T20 screwdriver to remove the four screws c.

Important

Removing the
Main-Board
Assembly

Carefully remove the lid assembly d.

Inspect the main seal in the lid for damage, and replace if necessary.

The circled numbers in this section refer to the items in Figure 5.3 on
page 127.
1.

Remove the auxiliary connector bung h (if fitted).

Remove the RF connector seal j using one of the tabs located at the
bottom of the seal—preferably by hand. If necessary, lift up the tap
using the blade of a small flat-bladed screwdriver. Do not damage the
seal with the screwdriver.

Use a Torx T10 screwdriver to remove the screws e connecting the
main board to the chassis.

Use a Torx T20 screwdriver to remove the screws i connecting the
heat-transfer block to the rear of the chassis.

Note

126

If an options board is fitted inside the lid, an options loom
will connect the options board to the internal options connector on the main board. In this case, carefully fold over
the lid and disconnect the loom.

Make sure not to touch the thermal paste on the chassis, the heattransfer block, and the underside of the main board. If the thermal
paste is contaminated, you must re-apply thermal paste as
described in “Fitting the Main-Board Assembly to the Chassis” on
page 133.

Holding a hand over the chassis to catch the main-board assembly,
turn the chassis upside down and tap its fins on the edge of the
workbench. This will release the heat-transfer block from the chassis.

With the 50W/40W radio, the gap pad 1) on the L-shaped ridge
must be replaced each time the main board is removed.

Disassembly and Reassembly

TM9100 Service Manual
© Tait Electronics Limited August 2005

Figure 5.3

Components of the radio body

Torx T20
22lb·in (2.5N·m)

Cx4
D

Torx T10
15lb·in (1.7N·m)

Ex5
F

1)
thermal
paste

G
H
Ix2
Torx T20
22lb·in (2.5N·m)

B
C
D
E
F

cover
screw M4x16 (x4)
lid assembly
screw M3x10 (x5)
main-board assembly

TM9100 Service Manual
© Tait Electronics Limited August 2005

J
3630z_01

G
H
I
J
1)

chassis
auxiliary connector bung
screws M4x16 (x2)
RF connector seal
gap pad (50W/40W radio only)

Disassembly and Reassembly

127

Disassembling the
Main-Board
Assembly

The circled numbers in this section refer to the items in Figure 5.4 on
page 129. This figure shows the 50W/40W configuration.
1.

Remove the power connector seal I.

Use a torque-driver with a 3/16 inch (5mm) socket to remove the
D-range screwlock fasteners H.

Use a torque-driver with a 9/16 inch (14mm) long-reach socket to
remove the RF connector nut 1!. Also remove the lock washer 1@.

Use a Torx T10 screwdriver to remove the three screws b securing
the main board 1$ to the heat-transfer block F.

Note

128

Make sure not to touch the thermal paste on the heat-transfer
block and the underside side of the main board. If the thermal
paste is contaminated, you must re-apply thermal paste as
described in “Reassembling the Main-Board Assembly” on
page 131.

Separate the main board 1$ from the heat-transfer block F.

Inspect the inner foam D-range seal E and the outer foam seal G,
and replace if necessary.

The gap pad 1) (50W/40W radio only) must be replaced each time
the heat-transfer block is separated from the main board.

To replace the power connector J:
■

With the 50W/40W radio, use a Torx T6 screwdriver to undo the
two screws C.

■

With the 25W radio, use a Torx T10 screwdriver to undo the two
screws C.

Disassembly and Reassembly

TM9100 Service Manual
© Tait Electronics Limited August 2005

Figure 5.4

Components of the main-board assembly
Torx T6
1lb·in (0.11N·m)
Torx T10
3lb·in (0.34N·m)

Cx2

Torx T10
15lb·in (1.7N·m)

D
E
F
G
J

1#
1@
1!

M3x10 screw (x3)
50W/40W radios:
M2.2x10 PT screw (x2)
25W radios:
K30x8 PT screw (x2)

D
E
F
G

auxiliary connector
inner foam D-range seal
heat-transfer block
outer foam seal

TM9100 Service Manual
© Tait Electronics Limited August 2005

thermal
paste

3/16 inch (5mm)
8lb·in (0.9N·m)

B
C

3631z_01

9/16 inch (14mm)
15lb·in (1.7N·m)

H
I
J
1)
1!
1@
1#
1$

D-range screwlock fastener (2x)
power connector seal
power connector
gap pad (50W/40W radio only)
RF connector nut
RF connector lock washer
RF connector
main board

Disassembly and Reassembly

129

Removing an
Options Board
(Optional)

The radio may be fitted with an options board in the lid assembly, which
may or may not have an external options connector fitted in a provision in
the lid assembly.
The circled numbers in this section refer to the items in Figure 5.5.
1.

If an external options connector is fitted:
■

■

Undo the two screws b and remove the protective rubber cap c
(if fitted).
Undo the two D-range screwlock fasteners d.

Undo up to nine screws h and remove the options board G from the
lid assembly E.

If an external options connector is fitted, a foam seal for the D-range
connector f is fitted to the inside of the lid. Remove the foam seal
only if it is damaged.

Reassembly is carried out in reverse order of the disassembly.
Figure 5.5

Removing an options board

3/16 inch (5mm)
8lb·in (0.9N·m)

b
c
e
f
g
h
Torx T10
17lb·in (1.9N·m)

B
C
D
E

130

screw 4-40x3/15 (x2)
protective rubber cap
D-range screwlock fastener 4-40 (x2)

3614z_01

F
G
H

foam seal for D-range connector
options board (example)
screw M3x10, self-tapping (x9)

lid assembly

Disassembly and Reassembly

TM9100 Service Manual
© Tait Electronics Limited August 2005

5.3

Reassembling the Radio Body
Inspect all disassembled parts for damage and replace them, if necessary.

Reassembling the
Main-Board
Assembly

The circled numbers in this section refer to the items in Figure 5.4 on
page 129. This figure shows the 50W/40W configuration.
1.

If the power connector has been replaced:
■

With the 50W/40W radio, use a Torx T6 torque-driver to
tighten the two screws C to 1lb·in (0.11N·m).

■

With the 25W radio, use a Torx T10 torque-driver to tighten the
two screws C to 3lb·in (0.34N·m).

If the outer foam seal E or the inner foam D-range seal G have been
removed, fit new seals to the heat-transfer block F.

With the 50W/40W radio, the rectangular gap pad 1) must be
replaced each time the heat-transfer block F is separated from the
main board 1$:
■

Remove any residue of the old rectangular gap pad from the
underside of main board and the heat-transfer block.

■

Peel off the transparent film on one side of the gap pad and evenly
press the gap pad on the contact surface of main board (refer to
Figure 5.6).

■

Peel off the transparent film on other of the gap pad.

Figure 5.6

Contact surfaces on the bottom side of the main board
contact surface of L-shaped gap pad

contact surface
of rectangular
gap pad

TM9100 Service Manual
© Tait Electronics Limited August 2005

tin-plated
copper plate

Audio-PA area

Disassembly and Reassembly

131

If the thermal paste on the heat-transfer block F or the tin-plated
cooper plate of the main board 1$ has been contaminated, new
thermal paste must be applied:
■

Remove any residue of the old thermal paste from both contact
surfaces.

■

Use Dow Corning 340 silicone heat-sink compound
(IPN 937-00000-55).

Important

■

Use a stiff brush to apply 0.1cm3 of thermal paste over the
complete contact surface on the tin-plated copper plate (refer to
Figure 5.6 on page 131).

Place the main board 1$ in position on the heat-transfer block F, and
push them together to spread the thermal paste.

Important

132

Ensure that no bristles from the brush come loose and
remain embedded in the paste. The paste needs to be
completely free of contaminants.

You must observe the following order of assembly to ensure
that the main board and the connectors are not assembled
under stress.

Use a torque-driver with a 3/16 inch (5mm) socket to fasten the
D-range screwlock fasteners H to 8lb·in (0.9N·m).

Fit the RF connector lock washer 1@. Use a torque-driver with a
9/16 inch (14mm) long-reach socket to fasten the RF connector nut
1! to 15lb·in (1.7N·m).

Use a torque-driver with a Torx T10 bit to fasten the three screws b
to 15lb·in (1.7N·m).

Loosen both the D-range screwlock fasteners H and the
RF connector nut 1!.

10.

Re-tighten both the D-range screwlock fasteners H and the
RF connector nut 1! to the torques indicated in steps 7 and 8.

11.

Fit the power connector seal I.

Disassembly and Reassembly

TM9100 Service Manual
© Tait Electronics Limited August 2005

Fitting the MainBoard Assembly to
the Chassis

The circled numbers in this section refer to the items in Figure 5.3 on
page 127. This figure shows the 50W/40W configuration.
1.

With the 50W/40W radio, the L-shaped gap pad 1) must be replaced
each time the main-board assembly F is removed from the chassis G:
■

Remove any residue of the old gap pad from the audio-PA area on
the underside of the main board (refer to Figure 5.6 on page 131)
and the L-shaped ridge of the chassis (refer to Figure 5.3 on
page 127).

■

Peel off the transparent film on one side of the gap pad and evenly
press the gap pad on the L-shaped ridge of the chassis.

■

Peel off the transparent film on other of the gap pad.

If the thermal paste on the heat-transfer block or the underside of the
main board has been contaminated, new thermal paste must be
applied:
■

Remove any residue of the old thermal paste from both contact
surfaces.

■

Use Dow Corning 340 silicone heat-sink compound
(IPN 937-00000-55).

Important

■

Ensure that no bristles from the brush come loose and
remain embedded in the paste. The paste needs to be
completely free of contaminants.

Use a stiff brush to apply 0.1cm3 of thermal paste on the heattransfer block (refer to Figure 5.3 on page 127).
Use a stiff brush to apply 0.01cm3 of thermal paste on the
audio-PA heat sink of the chassis (refer to Figure 5.3 on page 127)

Place the main-board assembly F in position in the chassis G.

Loosely screw in the two screws I through the heat-transfer block by
hand.

TM9100 Service Manual
© Tait Electronics Limited August 2005

Disassembly and Reassembly

133

While pressing down firmly on the diagonal edge of the PAD TOP can
(refer to Figure 5.7), use a Torx T20 torque-driver to tighten the two
screws I to 22lb·in (2.5N·m). This will ensure that the main board
is seated correctly on the bosses for the five internal screws E.

Figure 5.7

PAD TOP can on the top side of the main board

PAD TOP can

Closing the
Radio Body

134

Clean off any excess thermal paste on the heat-transfer block.

Screw in the five screws E through the main board by hand as far as
possible. Use a Torx T10 torque-driver to tighten the screws to
17lbf·in (1.9N·m).

Fit the RF connector seal j. Ensure that the seal is properly seated
around its entire periphery.

If an auxiliary connector bung h was fitted, fit the bung.

The circled number in this section refer to the items in Figure 5.3 on
page 127.
1.

If an internal options board is fitted inside the lid, connect the loom
to the internal options connector.

Inspect the main seal in the lid for damage, and replace if necessary.

Place the lid assembly D on the chassis G.

Use a Torx T20 torque-driver to tighten the four screws c to 22lbf·in
(2.5N·m).

Slide the cover b over the radio body and snap holes in the side of
the cover over the screw bosses.

Inspect the control-head seal for damage, and replace if necessary.

Disassembly and Reassembly

TM9100 Service Manual
© Tait Electronics Limited August 2005

5.4

Disassembling and Reassembling the Control Head
Disassemble only as much as necessary to replace the defective parts.
Reassembly is carried out in reverse order of the disassembly.
The circled numbers in this section refer to the items in Figure 5.9 on
page 137.
The connectors of the control-head board and the orientation of the speaker
and speaker clamp are illustrated in Figure 5.8.

Figure 5.8

With your fingers, pull off the volume control knob 1& .
Do not use any tools as this might cause damage.

Unscrew the two screws B and remove the adaptor flange C .

Disconnect the control-head loom D.

If an optional circuit board is fitted, unplug it from the control-head
board F (refer to Figure 5.8).

Note whether the speaker is connected or disconnected. If it is
connected, disconnect the speaker cable from the speaker connector
of the control-head board F (refer to Figure 5.8). Note that the radio
must be returned to the customer in its original configuration.

Release the lock of the LCD connector and unplug the loom of the
LCD assembly 1@ (refer to Figure 5.8). Note that the loom runs
through a slot in the space-frame J.

Speaker orientation and connectors of the control-head board

legs of the
speaker clamp

speaker terminals

pads for leads of
concealed microphone

connector for speaker

TM9100 Service Manual
© Tait Electronics Limited August 2005

connector for
loom of LCD assembly

connectors for
optional circuit board

connector for
control-head loom

3470z_01

Disassembly and Reassembly

135

Unscrew the four screws E and remove the control-head board F.

Pull the concealed microphone 1% capsule out of its rubber seal when
removing the control head-board F. If necessary, unsolder the leads
from the pads on the control-head board (refer to Figure 5.8).

Remove the light pipes H and I.

10.

The space-frame J clips into three clips of the front panel.
Unclip the spaceframe and remove it along with the two seals G.
Check the seals G and replace them, if necessary.

11.

Remove the speaker 1! and speaker clamp 1).

Important

12.

136

When fitting the speaker and the speaker clamp, observe the
orientation of the speaker terminals. Make sure that the
larger of the three legs of the speaker clamp is placed
between the two clips of the front panel assembly as shown
in Figure 5.8 on page 135.

Remove the LCD assembly 1@ , main keypad 1# , and power keypad
1$ .

Disassembly and Reassembly

TM9100 Service Manual
© Tait Electronics Limited August 2005

Figure 5.9

Components of the control head

Bx2

Torx T20
18lb·in (2.0N·m)

B
C
D
E
F
G
H
I
J
1)
1!
1@
1#
1$
1%
1^
1&

Torx T10
5.5lb·in (0.62N·m)

Ex4

H
I

M4 x 12 Taptite screw (x2)
adaptor flange
control-head loom assembly
3 x 10 PT screw (x4)
control-head board
space-frame seal (x2)
short light pipe
long light pipe
space-frame
speaker clamp
speaker
LCD assembly
main keypad
power keypad
concealed microphone
front panel assembly
knob for volume-control potentiometer

G
1)

1%
1#
1$

3451z_02

TM9100 Service Manual
© Tait Electronics Limited August 2005

Disassembly and Reassembly

137

138

Disassembly and Reassembly

TM9100 Service Manual
© Tait Electronics Limited August 2005

Servicing Procedures

Scope of Section

This section gives the full sequence of tasks required when servicing a
particular radio. These tasks are:
■

initial inspection, visual inspection and fault diagnosis

■

repair, final inspection, test and administration

For disassembly and reassembly instructions, refer to “Disassembly and
Reassembly” on page 123.

6.1

Initial Tasks

List of Tasks

The following tasks need to be carried out for all radios:
■

initial administration

■

visual inspection

■

powering up the radio

■

reading the programming file

■

obtaining the details of the Software Feature Enabler (SFE)

■

reading the calibration file

■

checking the user interface

■

checking any error messages

The following tasks only need to be carried out if they relate to the fault
reported:
■

checking the transmit and transmit-audio functions

■

checking the receive and receive-audio functions

Important

Observe the “General Information” on page 97.

Task 1 —
Initial
Administration

When a radio is received for repair, details of the Customer and the fault will
be recorded in a fault database. The fault reported by the Customer might
concern damage to or loss of a mechanical part, or the failure of a function
of the radio, or both.

Task 2 —
Visual Inspection

Check the radio for mechanical loss or damage, even if the fault concerns a
function failure only. Inspect the radio as follows:
■

knob for volume-control potentiometer

■

microphone grommet

■

rubber seal for RF connector

■

bung for auxiliary connector

■

bung for aperture for external options connector

TM9100 Service Manual
© Tait Electronics Limited August 2005

Servicing Procedures

139

The bung for aperture for external options connector should be replaced by
a cover seal if an external options connector is present. All the parts are
illustrated in “Spare Parts” on page 421. Except for the microphone
grommet, if any of these parts is missing or damaged, replace it as described
below. In the case of the microphone grommet, refer to the accessories
manual for the repair procedure.
Replace Damaged
or Missing Knob

Remove the volume-control knob if it is damaged. Push the replacement
knob onto the shaft of the volume-control potentiometer. Ensure that the
knob turns freely.

Replace Damaged
or Missing Seals
and Bungs

Remove any damaged seal or bung. Obtain a replacement seal for the
RF connector or a replacement bung from Spares kit 2. Order a
replacement cover seal (and screws) from TEL; the IPNs of the parts are
listed in “Spare Parts” on page 421. In fitting a replacement bung, ensure
that it is not upside down and that it is properly seated. To fit the seal for the
RF connector, first fit the upper part of the seal and then press down around
the sides of the seal to the bottom. Ensure that the seal is properly seated
around its entire periphery.

Check for
Additional Damage

Also check for damage to exterior parts that can be replaced only by partly
disassembling the radio. These parts are:
■

cover assembly for radio body

■

keys, lens and LCD of control head

■

front panel of control head

In the case of the front panel, inspect particularly the light pipes for the
STATUS LEDs and the membrane behind the speaker grille. If the radio is
reported to have a functional fault, continue with Task 3. Any additional
mechanical damage will be repaired during the course of rectifying the
functional fault. If the radio has no functional fault, repair any additional
damage as described below; conclude with the tasks of “Final Tasks” on
page 147.
Replace Damaged
Cover Assembly

Remove a damaged cover assembly. Obtain a replacement assembly from
Spares kit 2. The cover assembly comprises a cover and a label; the label is
permanently fixed to the cover. The IPNs of both items are given in “Spare
Parts” on page 421. If a spares kit is not available, order both items from
TEL. Fit the replacement cover assembly to the radio body.

Repair Damaged
Control Head

If the control head is damaged, detach it from the radio body as described
in “Removing and Mounting the Control Head” on page 124.
The procedure includes inspecting the interior of the control head for
evidence of other damage. Disassemble the control head and repair all
damage as described in “Disassembling and Reassembling the Control
Head” on page 135. Obtain replacement parts from Spares kit. Then reassemble the control head and re-attach it to the radio body.

140

Servicing Procedures

TM9100 Service Manual
© Tait Electronics Limited August 2005

Task 3 —
Power Up the Radio

With the radio connected to the test equipment as described in “Test
Equipment Setup” on page 105, attempt to power up the radio.
1.

Apply power to the radio. If the radio is programmed not to start on
power-on, press the ON/OFF switch.

Note

If the radio powers up but keeps resetting itself, check the powersensing circuitry. If the radio powers up but fails to enter usermode, or displays an error, refer to Table 6.1 on page 144.

If the radio powers up successfully, go to Task 4. If it does not, go to
Step 3.

Check the fuses, cables, and the power supply.

Check whether the control-head loom, the control head or the radio
body is faulty by first connecting a spare control-head loom and then
a spare control head.

If the control head is faulty, check the control-head connector
(pin 2: +13V8, pin 14: +3V3, pin 6: AGND), and repair or replace
the control-head board.

If the repair succeeded without the need for replacing the main-board
assembly, go to Task 4. Otherwise continue with Step 7.

If the main-board assembly was replaced or if the repair failed, reassemble the radio as described in “Disassembly and Reassembly” on
page 123. Conclude with the tasks of “Final Tasks” on page 147.

TM9100 Service Manual
© Tait Electronics Limited August 2005

Servicing Procedures

141

Task 4 —
Read the
Programming File

Given that the radio powers up, the next task is to read the radio’s
programming file or upload a default file.
1.

Use the programming application to read the programming file.

If the programming file can be read, save a copy on the test PC, and
go to Task 5. If not, go to Step 3.

If it seems that the file cannot be read, cycle the power to the radio
and again attempt to read the file. First cycling the power is essential
if the radio is programmed to power up in transparent-data mode
(both 1200 baud FFSK and Tait high-speed data) and if the selected
data port is the microphone connector.

If the programming file cannot be read, check whether:
■

the radio is connected to the correct serial port of the test PC,

■

the Mode switch of the test unit is set to Rx,

■

the programming application is set-up correctly. Refer to the
troubleshooting section of the online help.

If the programming file can be read now, save a copy on the test PC,
and go to Task 5. If not, go to Step 6.

Check whether the control-head loom, the control head or the radio
body is faulty by first connecting a spare control-head loom and then
a spare control head.

If the control head is faulty, check:
■

the control-head connector (pin 3: TXD, pin 7: RXD),

■

the microphone connector,

■

the path between the control-head connector and the microphone
connector,

and repair or replace the control-head board.

142

If the repair succeeded without the need for replacing the main-board
assembly, go to Step 9. Otherwise continue with Step 10.

If the programming file can be read now, save a copy on the test PC,
and go to Task 5. If the file still cannot be read, go to Step 10.

10.

Set up a suitable default programming file and attempt to upload it to
the radio

11.

If the upload succeeds, go to Task 6. If the upload fails, continue with
Step 12.

12.

Servicing Procedures

TM9100 Service Manual
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Task 5 —
Obtain the Details
of the Software
Feature Enabler
(SFE)

Use the programming application to obtain and record the details of any
software-enabled features (Tools > Optional Features).
For more information refer to the online help of the programming
application.

Task 6 —
Read the
Calibration File

Use the calibration application to read the calibration file and save it on the
test PC. If the calibration file cannot be read, set up a suitable default
calibration file and load it to the radio

Task 7 —
Check the
User Interface

Check the user interface as follows:
1.

Use the programming application to activate backlighting, deactivate
silent and quiet modes, and view the programmed function keys,
channels and scan groups.

Turn on the radio, make sure that the volume control is not set to low,
and check the start-up sequence:

■

the LEDs light up red briefly

■

the speaker gives two short beeps

■

LCD and keypad backlighting activates

■

the LCD displays a power-up message then a channel number, or
an error message.

Check for the following elements of the user interface:
■

volume control: Use CCTM command 1010 to read the volume
potentiometer. The returned value should be between 0 and 255.

■

LCD: Check visually or use CCTM command 1006 1 to switch
on all LCD elements. Power-cycle the radio to reset the LCD to
its original state.

■

PTT key: While pressing the PTT key, the transmit symbol
or
should appear on the radio display (unless transmit is inhibited
on the selected channel).

■

scroll and selection keys: Scroll through all settings and observe the
radio display.

■

function keys: Check whether the programmed function is
activated.

■

keypad: use CCTM command 1009 1 to turn on keypad
notification. Check that each keypress returns a different number.
CCTM command 1009 1 turns keypad notification off.

■

backlighting (if programmed): Any keypress should activate
backlighting.

If there is a fault in the user interface, repair the radio as described in
“Fault Finding of Control Head” on page 397.

If there is no fault, go to Task 8.

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Task 8 —
Check
Error Messages
Table 6.1

The radio may display an error message. Carry out the corrective actions
described in Table 6.1.

Error messages

Error message

Corrective action

Error E0001
Unknown

Turn the radio off and then back on.

Error E0002
Unknown

Continue with servicing tasks to locate the problem.

Error E0003
Corrupt FW

Re-download the radio’s firmware.

Error E0008
System error
0xabcdefgh

Turn the radio off and then back on. If the system error persists, download new
radio firmware.
To capture details of the system error, use CCTM command 204.

Temperature threshold
exceeded

Wait until the radio has cooled down.

Cannot tx

Go to Task 9 on page 145.

Out of lock

Go to “Frequency Synthesizer Fault Finding” on page 169.

Programming mode,
invalid radio ...

Re-program the radio with a new programming database. If the problem persists,
update or reload the radio’s firmware, and re-program the radio’s calibration
database.

144

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Task 9 —
Check the Transmit
and Transmit-Audio
Functions

If the radio does not transmit, this can be caused by:
■

the synthesizer not being in lock

■

no or wrong carrier power

■

a faulty speaker

■

no modulation

If the cause is already known, go directly to the relevant fault-finding
section.
Caution

Observe the servicing precautions for transmitter
issues listed on page 104.

Use CCTM command 101 x y 0 to set the transmit frequency to the
bottom of the band.

Use CCTM command 33 to set the radio to transmit mode.

Use CCTM command 72 to read the lock status.

If the synthesizer is in lock, go to Step 5. If the synthesizer is not in
lock, repair the radio as described in “Frequency Synthesizer Fault
Finding” on page 169.

Repeat Step 1 to Step 4 with the transmit frequency set to the top of
the band.

Use CCTM command 326 1 to set the power level to very low.

Connect a power meter and measure the transmit power.

If the carrier power is correct, go to Step 10. If the carrier power is
not correct, try to re-calibrate the radio.

If the re-calibration repairs the fault, go to “Final Tasks” on page 147.
If it does not, repair the radio as described in “Transmitter Fault
Finding (50W/40W Radios)” on page 245 and “Transmitter Fault
Finding (25W Radios)” on page 315.

10.

Repeat Step 6 to Step 9 with the power level set to high (326 4).

11.

Check whether the speaker is the source of the fault, as described in
“Speaker Faulty” on page 414.

12.

If the radio transmits audio now, the original speaker was faulty.
Reassemble the radio and go to “Final Tasks” on page 147. If the
radio still fails to transmit, reconnect the original speaker and go to
Step 13.

13.

After having eliminated the synthesizer, the transmitter circuitry, and
the speaker as cause for the fault, repair the radio as described in
“CODEC and Audio Fault Finding” on page 371.

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14.

Task 10 —
Check the Receive
and Receive-Audio
Functions

If the radio does not receive, this can be caused by:
■

the synthesizer not being in lock

■

no carrier detected

■

a faulty speaker or volume control

■

no modulation

If the cause is already known, go directly to the relevant fault-finding
section.

146

Use CCTM command 101 x y 0 to set the receive frequency to the
bottom of the band.

Use CCTM command 72 to read the lock status.

If the synthesizer is in lock, go to Step 5. If the synthesizer is not in
lock, repair the radio as described in “Frequency Synthesizer Fault
Finding” on page 169.

Repeat Step 1 to Step 3 with the receive frequency set to the top of
the band

Feed a signal without modulation on the receive channel at –47dBm.
Check for maximum RSSI using:
■

the

indicator on the radio display

■

the green status LED

■

CCTM command 63 should return the fed signal strength
±1dBm.

Repeat the check in Step 5 with –117dBm. The RSSI indicator
should show as empty or close to empty.

If the carrier is detected correctly, go to Step 9. If the carrier is not
detected correctly, try to re-calibrate the radio.

If the re-calibration repairs the fault, go to “Final Tasks” on page 147.
If it does not, repair the radio as described in “Receiver Fault
Finding” on page 227.

Check whether the speaker is the source of the fault, as described in
“Speaker Faulty” on page 414.

10.

If the radio receives audio now, the original speaker was faulty.
Reassemble the radio and go to “Final Tasks” on page 147. If the
radio still fails to receive, reconnect the original speaker and go to
Step 11.

11.

Use CCTM command 804 to read the status of the volume
potentiometer.

Servicing Procedures

TM9100 Service Manual
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6.2

If the volume potentiometer is faulty, repair it as described in
“Volume Control Faulty” on page 416. If it is not faulty, go to
Step 13.

13.

After having eliminated the synthesizer, the receiver circuitry, the
speaker, and the volume potentiometer as cause for the fault, repair
the radio as described in “CODEC and Audio Fault Finding” on
page 371.

14.

Final Tasks

List of Tasks

Task 1 —
Repair

12.

The following tasks need to be carried out for all radios:
■

repair

■

enable software features (if applicable)

■

final inspection

■

final test

■

final administration

The fault diagnosis will have resulted in the repair or replacement of the
main-board assembly. This section describes the steps after completion of
the fault diagnosis:
1.

Use the programming and calibration applications to load the programming and calibration files read or set-up in “Initial Tasks”.

Note

If the radio had to be reprogrammed with a default programming
file, the following additional actions are required: If the radio is to
be returned direct to a Customer who has no programming facilities, the appropriate programming file needs to be obtained and
uploaded (or the data obtained to create the file). If the radio is to
be returned to a Dealer or direct to a Customer who does have
programming facilities, the Dealer or Customer respectively need
to be informed so that they can program the radio appropriately.

Note

If the main-board assembly has been replaced, certain software
features may need to be enabled before the programming file can
be loaded. See Task 2 on page 148.

Test the radio as described in “Final Test” on page 149.
It may be necessary to also re-calibrate to make the radio functional,
in particular if the main-board assembly had to be replaced or if a
default calibration file had to be loaded. Refer to the online help of
the calibration application.

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If the main-board assembly has been replaced, level-1 service centers
should return the faulty board to the nearest ASC, and level-2 service
centers should return the board or assembly to the ISC, if deemed
necessary. Supply details of the fault and, if applicable, the attempted
repair. Go to step Step 6.
If the main-board assembly has not been replaced, go to Step 4.

Task 2 —
Enable Software
Features (SFE)

148

Replace any cans removed. Refer to “Shielding Cans and
Connectors” on page 108.

Re-test the radio as described in “Final Test” on page 149.

Reassemble the radio as described in “Disassembly and Reassembly”
on page 123.

Reconnect the radio to the test equipment and carry out a final
calibration of the radio. Refer to the online help of the calibration
application.

If the main-board assembly has been replaced, ensure that the correct
software features, if any, are enabled for the Customer. If software features
need to be enabled, a special licence file is required for the replacement
main-board assembly. The file must allow for the enabling of the same
software features as in the original assembly. Proceed as follows:
1.

If it was possible to read the software features in “Obtain the Details
of the Software Feature Enabler (SFE)” on page 143, go to Step 2.
If it was not possible, go to Step 3.

Reading the software features will have revealed if any software
features were enabled for the radio under repair. If there were, go to
Step 3. If there were none, go to Task 3.

Technicians not at a CSO should contact their CSO regarding the
radio’s software features. Technicians at CSOs should contact
Technical Support at TEL.

Supply the serial number of the radio under repair, and the serial
number of the replacement main-board assembly (located on a label
on the main-board assembly).

If it is known that the radio had software features enabled, go to
Step 6. Otherwise go to Step 7.

Ask the CSO (or TEL) for a licence file for the replacement mainboard assembly. The CSO will supply the required file. Go to Step 8.

Ask the CSO (or TEL) if the radio under repair had any software
features enabled, and if so, to send a licence file for the replacement
main-board assembly. The CSO (or TEL) will either indicate that the
radio had no software features enabled or supply the required file. If
the radio had no software features enabled, go to Task 3. If the
required file was supplied, go to Step 8.

Servicing Procedures

TM9100 Service Manual
© Tait Electronics Limited August 2005

On receiving the licence file, run the programming application on the
test PC. On the menu bar click Tools > Optional Features.
The Software Feature Enabler dialog appears.

Use the licence file to enable the appropriate software features.
The procedure is given in the on-line help facility under the heading
Enabling a feature. Go to Task 3.

Task 3 —
Final Inspection

Make a final inspection of the exterior to check that no mechanical parts
were damaged during the repair. Repeat the inspection given in “Visual
Inspection” on page 139. Rectify any damage.

Task 4 —
Final Test

Test the radio to confirm that it is fully functional again. The recommended
tests are listed in Table 6.2 to Table 6.4. (The calibration application can be
used for many of these tests.) It is good practice to record the test results on
a separate test sheet. A copy of the test sheet can be supplied to the Customer
as confirmation of the repair.

Task 5 —
Final
Administration

The final administration tasks are the standard workshop procedures for
updating the fault database and returning the repaired radio to the Customer
with confirmation of the repair.
If the radio could not be repaired for one of the following reasons:
■

fault not located

■

repair of fault failed

■

required repair is level-3 repair

Level-1 service centers should return the faulty radio to the nearest ASC,
and level-2 service centers should return the radio to the ISC. Supply details
of the Customer, the fault and, if applicable, the attempted repair.

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Table 6.2

Final tests of transmitter function

Test

Limits

Error in transmit frequency

+100 Hz to –100 Hz

Transmit power:
• High
• Medium
• Low
• Very low

23.2 W to 29.2 W
11.1 W to 14.0 W
4.6 W to 5.8 W
0.9 W to 1.2 W

Current at high power:
• B1-band radios
• H5-band radios
• H6-band radios

< 5.5 A
< 6.5 A
< 6.5 A

Peak deviation (sweep tone of 300 Hz to 3 kHz):
• Narrow-band
• Medium-band
• Wide-band

< 2.5 kHz
< 4.0 kHz
< 5.0 kHz

Distortion:
• 1 kHz at 1.5 kHz deviation (narrow-band)
• 1 kHz at 3.0 kHz deviation (wide-band)

< 3%
< 3%

CTCSS (continuous-tone-controlled subaudible signaling) deviation:
• Narrow-band
• Medium-band
• Wide-band

250 to 350 Hz
500 to 560 Hz
580 to 680 Hz

Table 6.3

Final tests of receiver functions

Test

Limits

Receive sensitivity

<118 dBm for 12 dB SINAD

Mute opening:
• Country
• City
• Hard

>6 dB and <10 dB SINAD
>8 dB and <14 dB SINAD
>18 dB and <22 dB SINAD

Audio power (maximum volume at –47 dBm):
• At “RX AUDIO/SINAD” connector on test unit
• At pins 3 (SPK–) and 4 (SPK+) of power connector on radio

>500 mVrms
>5.00 Vrms

Distortion (at –47 dBm, 60% rated system deviation at 1kHz,
with volume set to give 3 W into 16 Ω load)

<3.00%

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Table 6.4

Final tests of general radio functions

Test

Description

PTT switch

Check that PTT switch functions.

Microphone

Check operation of microphone.
Check operation of hook-switch.

Data communications

Test 1200 baud data transmission (standard).
Test Tait high-speed data transmission (if feature is enabled).

Direct-connect GPS
(global positioning system)

Check that GPS poll returns correct position (if feature is enabled).

Selcall

Check that radio encodes selcall.
Check that radio decodes selcall.

Audio tap points and digital I/O

Check configuration of programmed options and test operation of
these lines to confirm that Customer requirements are satisfied.

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Power Supply Fault Finding

Fault-Diagnosis
Tasks

Fault diagnosis of the power-supply circuitry is divided into six tasks:
■

check inputs to SMPS

■

check 3.3 V supply

■

check linear regulators

■

check power-up

■

check power-up options

The regulators of concern in the third task are those for the 9V, 6V, 3V and
2.5V supplies.
Three Types of Fault

Which of the above tasks are applicable depends on the nature of the fault:
■

radio fails to power up

■

power-up option has failed

■

external power at connector has failed

With the first fault, either the radio fails to power up immediately when
power is applied, or it fails to power up when power is applied and the
ON/OFF key is pressed. In this case carry out Task 1 to Task 3. With the
second fault, the radio powers up when the ON/OFF key is pressed, but not for
a power-up option for which it is configured. In this case carry out Task 4
and Task 5. With the third fault, the external power required at a particular
connector is no longer present. In this case carry out Task 6.

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Task 1 —
Check Inputs to
SMPS

The test equipment and radio should be set up as described in “Test
Equipment Setup” on page 105. If not already done, remove the mainboard assembly from the chassis. Connect the control head to the assembly.
Then check the SMPS as follows:
1.

Use a multimeter to check the supply voltage at pin 7 of IC602
(see Figure 7.1) in the SMPS circuitry; the voltage should be:
pin 7 of IC602: 13.8 V DC

If it is, go to Step 5. If it is not, go to Step 2.
2.

Disconnect the 13.8V supply at the power connector PL100. Check
for continuity and shorts to ground in the path between the power
connector PL100 and pin 7 of IC602 (see Figure 7.1). Locate and
repair the fault.

Reconnect the 13.8V supply. Confirm the removal of the fault by
measuring the voltage at pin 7 of IC602. If the voltage is correct,
continue with Step 4. If it is not, the repair failed; replace the mainboard assembly and go to “Final Tasks” on page 147.

Press the ON/OFF key. If the radio powers up, return to “Initial Tasks”
on page 139. If it does not, go to Step 5.

Check the digital power-up signal at pin 5 of IC602
(see Figure 7.1); the signal is active high, namely, when the voltage
exceeds 2.0V DC. Measure the voltage at pin 5.
pin 5 of IC602: more than 2.0 V DC

If it exceeds 2.0V, go to Task 2. If it does not, go to Step 6.

154

Keep the probe of the multimeter on pin 5 of IC602 and press the
ON/OFF key. The voltage should exceed 2.0V DC while the key is
depressed. If it does, go to Task 2. If it does not, go to Step 7.

Disconnect the 13.8V supply at the power connector PL100. Check
for continuity and shorts to ground in the path from pin 5 of IC602,
via R600 and via Q709 in the interface circuitry (see Figure 8.4), to
pin 9 of the control-head connector SK100 (ITF PSU ON OFF line).
Locate and repair the fault. Go to Step 8.

Reconnect the 13.8V supply. Press the ON/OFF key. If the radio powers
up, return to “Initial Tasks” on page 139. If it does not, go to Step 9.

With the probe of the multimeter on pin 5 of IC602 (see Figure 7.1),
press the ON/OFF key again. The voltage should exceed 2.0V DC
while the key is depressed. If it does, go to Task 2. If it does not, the
repair failed; replace the main-board assembly and go to “Final Tasks”
on page 147.

Power Supply Fault Finding

TM9100 Service Manual
© Tait Electronics Limited August 2005

Figure 7.1

Important components of the power-supply circuitry (bottom side),
including 3.3V regulator IC602

pin 7

pin 5

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Power Supply Fault Finding

155

Figure 7.2

Important components of the power-supply circuitry (top side),
including 9V regulator IC601

Task 2 —
Check 3.3 V Supply

If the inputs at pin 5 and pin 7 of IC602 in the SMPS circuitry are correct,
but the radio fails to power up, then the 3.3V DC supply needs to be
investigated.
1.

First determine as follows if a fault on the digital board is affecting the
supply or preventing the radio from powering up: While keeping the
ON/OFF key depressed, measure the supply at the 3V3 test point near
the corner of the digital board (see Figure 7.2). The voltage is 3.3V
when there is no fault.
3V3 test point: 3.3 ± 0.1 V DC

If the voltage is correct, the digital board is faulty; replace the mainboard assembly and go to “Final Tasks” on page 147. If the voltage is
not correct, go to Step 2.

156

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Disconnect the 13.8V supply at the power connector. Remove R199
(see Figure 7.1). Reconnect the 13.8V supply.

With the probe of the multimeter on the 3V3 test point, press the
ON/OFF key. If the voltage is now 3.3 ± 0.1V, the digital board is faulty;
replace the main-board assembly and go to “Final Tasks” on
page 147. If the voltage is still not correct, go to Step 4.

If the digital board is functional, the fault is on the main board.
Replace R199. Disconnect the 13.8V supply. Use the multimeter to
measure the resistance between the 3V3 test point and ground.
If there is a short circuit, continue with Step 5. If there is no short
circuit (but the voltage is wrong), go to Step 7.

Search for shorts to ground in the components C603, C612, C613,
C618, D606 of the SMPS circuitry (see Figure 7.1) as well as in the
CODEC and interface circuitry. Repair any fault and repeat the
resistance measurement of Step 4 to confirm the removal of the fault.
If there is no fault, go to Step 6. If the fault remains, the repair failed;
replace the main-board assembly and go to “Final Tasks” on
page 147.

Reconnect the 13.8V supply. Press the ON/OFF key. If the radio powers
up, return to “Initial Tasks” on page 139. If the radio fails to power
up, disconnect the 13.8V supply and go to Step 7.

Measure the resistance of L601 (see Figure 7.1). The resistance
should be virtually zero. If it is, go to Step 8. If it is not, replace L601.
Reconnect the 13.8V supply and press the ON/OFF key. If the radio
powers up, return to “Initial Tasks” on page 139. If the radio fails to
power up, disconnect the 13.8V supply and go to Step 8.

Remove the CDC BOT can. Remove IC603 (3.0V regulator) and
IC604 (2.5V regulator) (see Figure 7.3). Reconnect the 13.8V
supply and press the ON/OFF key. If the 3.3V supply is restored, go to
Task 3 to check each regulator (3.0V and 2.5V) in turn. If the 3.3V
supply is not restored, continue with Step 9.

Suspect IC602. Disconnect the 13.8V supply. Replace IC602 with a
spare (see Figure 7.1). Resolder IC603 and IC604 in position
(see Figure 7.3). Reconnect the 13.8V supply and press the ON/OFF
key. If the radio powers up, return to “Initial Tasks” on page 139.
If the radio fails to power up, the repair failed; replace the main-board
assembly and go to “Final Tasks” on page 147.

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Figure 7.3

Power-supply circuitry under the CDC BOT can, including 3V regulator IC603 and 2.5V
regulator IC604

TP601

LO2 BOT CAN

CAN FOR
DIGITAL
BOARD

Task 3 —
Check Linear
Regulators

158

This task describes the general procedure for checking any linear regulator.
There are two possible faults: either the regulator has failed and prevents the
radio from powering up, or the regulator voltage is incorrect. (The regulator
IC might or might not have been removed during earlier checks.)
1.

Disconnect the 13.8 V supply. Check for continuity and shorts to
ground (if not already done) on the input, output and control line of
the relevant regulator IC. Repair any fault.

If the regulator IC has been removed, resolder it in position.

Reconnect the 13.8 V supply and press the ON/OFF key. If the radio
powers up or the correct regulator voltage is restored, return to
“Initial Tasks” on page 139. If the repair failed, go to Step 4.

Disconnect the 13.8 V supply. Replace the regulator IC with a spare.
Reconnect the 13.8 V supply and press the ON/OFF key. If the radio
powers up or the correct regulator voltage is restored, go to “Final
Tasks” on page 147. If the repair failed, replace the main-board
assembly and go to “Final Tasks” on page 147.

Power Supply Fault Finding

TM9100 Service Manual
© Tait Electronics Limited August 2005

Task 4 —
Check Power-up
Configuration

The radio may be configured for one or more of the following power-up
options:
■

battery power sense

■

auxiliary power sense

■

emergency power sense

■

internal-options power sense

A particular option is implemented by inserting the link mentioned in
Table 7.1. If there is a fault with a power-up option for which the radio is
configured, first confirm that the configuration is correct:

Table 7.1

Confirm that the correct link or links have been inserted for the
required power-up options (see Figure 7.2 and Table 7.1). For all
except the battery-power-sense option, also check the radio’s
programming as follows:

Open the “Programmable I/O” form.

Under the “Digital” tab, scroll to the relevant digital line listed in the
“Pin” field:
■

internal-options power sense:

IOP GPIO7

■

auxiliary power sense:

AUX GPI3

■

emergency power sense:

AUX GPI2

For the first two lines, confirm that the “Power Sense (Ignition)” option
has been selected in the “Action” field, and “High” or “Low” in the “Active”
field. For the third line, confirm that “Enter Emergency Mode” has been
selected.

If the link and programming settings are correct, go to Task 5. If they
are not, rectify the settings and check if the fault has been removed.
If it has, return to “Initial Tasks” on page 139. If it has not, go to
Task 5.

Implementation of the power-up options

Power-up
option

Link to
insert

Factory
default

Activation mechanism

Connector

Battery
power sense

LK1

Link in

Connection of 13.8V supply

Power connector

Auxiliary
power sense

LK2

Link in

AUX GPI3 line goes high
(If LK1 is in, line floats high;
if LK1 is out, line floats low)

Pin 4 of
auxiliary connector

Emergency
power sense

LK3

Link in

AUX GPI2

Internal-options
power sense

LK4

Link out

IOP GPIO7

TM9100 Service Manual
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line goes low

Pin 5 of
auxiliary connector

line goes high

Pin 15 of
internal-options connector

Power Supply Fault Finding

159

Task 5 —
Check Power-up
Options

The functioning of the power-up options may be checked as described in
Step 1 to Step 4 below. Carry out the procedure in the appropriate step or
steps. In all four cases the procedure involves checking the digital power-up
signal at pin 5 of IC602. For a particular option, the activation mechanism
is the condition that results in the power-up signal becoming active (the
signal is active high).
1.

For the battery power-sense option the link LK1 should be inserted
(see Figure 7.2). Check the power-up signal at pin 5 of IC602
(see Figure 7.1) while first disconnecting and then reconnecting the
13.8V DC supply at the power connector.
The power-up signal should go high when the power is reconnected.
If it does, conclude with Step 5. If it does not, check for continuity
and shorts to ground between the link LK1 and the +13V8 BATT input
at the power connector PL100. Repair any fault and go to Step 5.

For the auxiliary power-sense option the link LK2 should be inserted
(see Figure 7.2). Connect +3.3V DC (more than 2.6V to be
precise) from the power supply to the AUX GPI3 line (pin 4 of the
auxiliary connector SK101). Check that the power-up signal at pin 5
of IC602 (see Figure 7.1) is high.
Remove the +3.3V supply and ground the AUX GPI3 line (to be precise
the voltage on the line should be less than 0.6V). If the power-up
signal is now low, conclude with Step 5. If it is not, check for
continuity and shorts to ground between D601 (see Figure 7.1) and
pin 4 of the auxiliary connector SK101. Repair any fault and go to
Step 5.

For the emergency power-sense option the link LK3 should be
inserted (see Figure 7.2). Connect the AUX GPI2 line (pin 5 of the
auxiliary connector SK101) to ground. Check that the power-up
signal at pin 5 of IC602 (see Figure 7.1) is high.
Remove the connection to ground. If the power-up signal is now
low, conclude with Step 5. If it is not, check for continuity and shorts
to ground in the path from D601 (see Figure 7.1), via Q600
(see Figure 7.2), to pin 5 of the auxiliary connector SK101. Repair
any fault and go to Step 5.

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© Tait Electronics Limited August 2005

For the internal-options power-sense option the link LK4 should be
inserted (see Figure 7.2). Connect +3.3V DC (more than 2.6V to
be precise) from the power supply to the IOP GPIO7 line (pin 15 of the
internal-options connector SK102). Check that the power-up signal
at pin 5 of IC602 (see Figure 7.1) is high.
Remove the +3.3V supply and ground the IOP GPIO7 line (to be
precise the voltage on the line should be less than 0.6V). If the powerup signal is now low, conclude with Step 5. If it is not, check for
continuity and shorts to ground between D604 (see Figure 7.1) and
pin 15 of the internal-options connector SK102. Repair any fault and
go to Step 5.

After checking all the relevant power-up options, and if necessary
repairing any faults, go to “Final Tasks” on page 147. If the fault
could not be found or repairs failed, replace the main-board assembly
and go to “Final Tasks” on page 147.

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Task 6 —
Check Provision of
External Power

External power is supplied to pin 8 of the auxiliary connector SK101.
The power is normally switched, but will be unswitched if all the links LK5
to LK8 are inserted. (With all the links inserted, the power at the other
connectors is also unswitched.)
External power, either switched or unswitched, is supplied to pin 2 of the
control-head connector SK100. The power is switched or not depending on
the links LK5 and LK6:
■

switched power: LK5 in, LK6 out

■

unswitched power: LK5 out, LK6 in

External power is also supplied to pin 1 of the internal-options connector
SK102. The power is switched or not depending on the links LK7 and LK8:
■

switched power: LK7 in, LK8 out

■

unswitched power: LK7 out, LK8 in

If there is a fault with the supply of external power to any of these
connectors, first confirm the link settings required and then carry out the
following procedure:

162

With the radio powered up, confirm that 13.8V DC is present at pin
3 of IC605 (see Figure 7.1) and more than 3V DC at pin 2.

Check that 13.8 V is present at pin 5 of IC605. If there is, go to
Step 3. If there is not, go to Step 4.

Check for an open circuit between pin 5 of IC605 and the relevant
pin of the connector in question. Repair any fault, confirm the
removal of the fault, and go to “Final Tasks” on page 147. If the
repair failed or the fault could not be found, replace the main-board
assembly and go to “Final Tasks” on page 147.

Check for continuity between pin 5 of IC605 and the relevant pin of
the connector in question. Check for shorts to ground, check C718
at the auxiliary connector (see Figure 7.1), and check C715 at the
internal-options connector (see Figure 8.2).

Repair any fault found in the above checks. If no fault could be
found, replace IC605.

Confirm the removal of the fault and go to “Final Tasks” on
page 147. If the repair failed, replace the main-board assembly and go
to “Final Tasks” on page 147.

Power Supply Fault Finding

TM9100 Service Manual
© Tait Electronics Limited August 2005

Interface Fault Finding

Introduction

This section covers the diagnosis of faults involving signals output from or
input to the radio’s internal circuitry via the control-head, internal options,
power, or auxiliary connectors. For most inputs and outputs, filtering or
basic processing is applied between the internal circuitry and the connectors.

Internal and
Connector Signals

The signals at the internal circuitry and those at the connectors are
distinguished as internal signals and connector signals respectively. On the
circuit diagram for the internal circuitry, dashed lines enclose connector
signals. Internal signals are all named signals outside these enclosures. In
Figure 8.1, which shows part of the internal options connector as an
example, IOP GPIO7 is a connector signal and ITF IOP GPIO7 is an internal signal.

Figure 8.1

Example illustrating the convention for internal and connector signals

TO
INTERNAL
OPTIONS
CONNECTOR
+3V3_CL
3

+3V3

D705
BAV70W

R723
33K

ITF_IOP_GPO7

R731
1K0

+3V3_CL
3

D706
BAV70W

R724
33K
R732
1K0

+3V3_CL
3

ITF_IOP_GPO5

IOP_GPIO6
1B2

+3V3

D706
BAV70W

R725
33K
R733
1K0

Types of Signals

1B2
6B4

+3V3

ITF_IOP_GPO6

IOP_GPIO7

IOP_GPIO5
1B2

The connector and internal signals can be of three types:
■

output lines

■

input lines

■

bi-directional lines

For diagnosing faults in these three cases, carry out Task 1, Task 2 or Task 3
respectively. Where components need to be replaced to rectify faults, refer
to Figure 8.3 to Figure 8.4 for the locations of the components. These
figures show the three areas of the main board where the components of the
interface circuitry are situated.

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Figure 8.2

Components of the interface circuitry (top side near the CDC TOP and IF TOP cans)
IF TOP CAN

Figure 8.3

164

CDC TOP CAN

Components of the interface circuitry (top side at the corner)

Interface Fault Finding

TM9100 Service Manual
© Tait Electronics Limited August 2005

Task 1 —
Check Output Lines

For an output line suspected or reported to be faulty, compare actual and
expected signals as described below. If necessary, determine what an
expected signal should be by copying the faulty radio’s programming file
into a serviceable radio and measuring the relevant points on the latter.
1.

Check the electrical signal at the appropriate pin of a connector
mated to the radio connector in question. If the expected connector
signal is not present, go to Step 3. If it is, go to Step 2.

If the expected signal is present, there might be no fault on that line
or there could be an intermittent fault. Subject the radio to mild
mechanical shock or vibration, or to a temperature change. This
might expose any intermittent contact, in which case go to Step 3.

If the expected signal is not present, check whether the expected
internal signal is present. If it is, go to Step 5. If it is not, go to Step 4.

The fault lies with the radio’s internal circuitry. If the power-supply
circuitry or the CODEC and audio circuitry is suspect, continue with
the fault diagnosis as in “Power Supply Fault Finding” on page 153
and “CODEC and Audio Fault Finding” on page 371 respectively. If
the digital board is suspect, replace the main-board assembly and go
to “Final Tasks” on page 147.

The fault lies in the filtering, basic processing, or connector for the
line under test. Re-solder components or replace damaged or faulty
components as necessary. Confirm the removal of the fault and go to
“Final Tasks” on page 147. If the fault could not be found, replace
the main-board assembly and go to “Final Tasks” on page 147.

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Figure 8.4

166

Components of the interface circuitry (bottom side)

Interface Fault Finding

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Task 2 —
Check Input Lines

Task 3 —
Bi-directional Lines

For an input line suspected or reported to be faulty, proceed as follows:
1.

For a suspect CH ON OFF line, go to Step 4. For all other input lines go
to Step 2.

For the suspect line, apply a 3.3V DC test signal to a connector mated
to the radio connector in question.

Check the internal signal for the line under test. If 3.3V DC is
present, go to Step 7. If it is not, go to Step 8.

For the CH ON OFF line, apply a short to ground on pin 5 of a connector
mated to the control-head connector. Check that there is 3.9V DC
present on the ITF ON OFF line, and that PSU ON OFF is approximately
equal to the radio’s primary supply voltage, nominally 13.8V DC.

Remove the short on the connector. Check that, with CH ON OFF
open-circuit, both ITF ON OFF and ITF PSU ON OFF are close to 0.0V.

If the voltages given in Step 4 and Step 5 are observed, go to Step 7.
If they are not, go to Step 8.

The fault lies with the radio’s internal circuitry. If the power-supply
circuitry or the CODEC and audio circuitry is suspect, continue with
the fault diagnosis as in “Power Supply Fault Finding” on page 153
and “CODEC and Audio Fault Finding” on page 371, respectively.
If the digital board is suspect, replace the main-board assembly and go
to “Final Tasks” on page 147.

The fault lies in the filtering, basic processing, or connector for the
line under test. Re-solder components or replace faulty com-ponents
as necessary. Confirm the removal of the fault and go to “Final Tasks”
on page 147. If the fault could not be found, replace the main-board
assembly and go to “Final Tasks” on page 147.

For a bi-directional line suspected or reported to be faulty, proceed as
described below. In the procedure the direction of the line will need to be
configured. For information on this topic consult the on-line help facility
on the programming application’s “Programmable I/O” page.
1.

Configure the suspect line as an output, and then carry out the
procedure given in Task 1.

Configure the suspect line as an input, and then carry out the
procedure given in Task 2.

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Interface Fault Finding

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Frequency Synthesizer Fault Finding
This section covers the diagnosis of faults in the frequency synthesizer.
The sections are divided into the following:

Introduction

■

Initial checks

■

Fault diagnosis of RF PLL circuitry

■

Fault diagnosis of FCL circuitry

The initial checks will indicate whether it is the RF PLL or the FCL that is
suspect. Note that the synthesizer is a closed-loop control system. A fault in
one area can cause symptoms to appear elsewhere. Locating the fault can
therefore be difficult.
Measurement
Techniques

Table 9.1
Command

The radio must be in CCTM for all the fault-diagnosis procedures of this
section. The CCTM commands required are listed in Table 9.1. Full details
of the commands are given in “Computer-Controlled Test Mode
(CCTM)” on page 112. Use an oscilloscope with a x10 probe for all voltage
measurements required. The signals should appear stable and clean.
Consider any noise or unidentified oscillations as evidence of a fault
requiring investigation. Use a frequency counter for all measurements of
high frequencies. The RF power output from the frequency synthesizer will
not exceed 10mW. If a probe is used for frequency measurements, use the
x1 setting.

CCTM commands required for the diagnosis of faults in the frequency synthesizer
Description

72
101 x y 0
205
301 0 10
302 0 10

Read lock status of RF PLL, FCL and LO2 — displays xyz (0=not in lock, 1=in lock)
Set transmit frequency (x in hertz) and receive frequency (y in hertz) to specified values
Reset calibration parameters to their default values
Calibrate VCXO of FCL
Calibrate VCO(s) of RF PLL

334 x
335 x
389 x
393 1 x

Set synthesizer on (x=1) or off (x=0) via DIG SYN EN line
Set transmit-receive switch on (x=1) or off (x=0) via DIG SYN TR SW line
Set synthesizer mode to slow (x=0) or fast (x=1)
Write data x to FPGA

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9.1

Initial Checks

Types of checks

There are two different types of initial checks, which are covered in the
following tasks:
■

Task 1: calibration checks

■

Task 2: lock status

Which, if any, of these tasks needs to be carried out depends on the
symptoms of the fault.
Symptoms of Fault

The symptoms of the fault may be divided into three categories:
■

radio fails to power up and System error is displayed

■

Out of lock is displayed

■

radio is in lock but exhibits transmit or receive fault

In the first two cases the checks of Task 1 and Task 2 respectively are
required. In the last case there are several symptoms; these are listed below.
Transmit and
Receive Faults

A transmit or receive fault will be implied by one of the following
consequences:
■

radio fails to receive or receive performance is degraded

■

radio fails to enter transmit mode

■

radio exits transmit mode unexpectedly

■

radio enters transmit mode but fails to transmit

■

radio enters transmit mode but transmit performance is degraded

With a fault of this kind, neither of the initial tasks is required.
Fault diagnosis should begin with “Power Supplies” on page 173.
Summary

To summarize, given the nature of the fault, proceed to the task or section
indicated below:
■

Task 1: system error

■

Task 2: lock error

■

“Power Supplies”: transmit or receive fault

The checks of Task 1 and Task 2 will indicate the section with which the
fault diagnosis should continue. Note that there are some differences in the
fault-diagnosis procedures, depending on whether the radio is a UHF (H5
and H6 bands) or VHF (B1 band) radio. The product-code label on the
radio body will identify the frequency band as described in “Product
Codes” on page 16.

170

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Task 1 —
System Error

A system error indicates a fault in the calibration of either the FCL or the
frequency synthesizer. To determine which is faulty, calibrate the VCXO
and the transmit VCO as described below. (Always calibrate the former first,
because the latter depends on the former.)
1.

Place the radio in CCTM.

Enter the CCTM command 301 0 10 to calibrate the VCXO.
The response will be one of the following three messages:
■

“passed sanity check. Cal’d values put into effect”

■

“failed sanity check. Cal’d values not in effect”

■

“Cal failed: lock error”

The first two messages will be preceded by four calibration values.
3.

In the case of the first message (passed), go to Step 4. In the case of
the second and third messages (failed), the FCL is suspect; go to
“Power Supply for FCL” on page 215.

Enter the CCTM command 302 0 10 to calibrate the transmit VCO.
The response will be one of the three messages listed in Step 2.
The first two messages will be preceded by eight calibration values.
Reset the radio and re-enter CCTM.

If the calibration succeeded but the system error persists, replace the
main-board assembly and go to “Final Tasks” on page 147. In the
case of the second message (failed sanity check), go to Step 6. In the
case of the third message (calibration failed), go to Step 8 (UHF
radios) or “Power Supplies” on page 173 (VHF radios).

Enter the CCTM command 205 to reset the calibration values to the
default values. Then enter the CCTM command 302 0 10 again to
calibrate the transmit VCO.

If the calibration succeeded, confirm the removal of the fault, and go
to “Final Tasks” on page 147. If the calibration failed, go to Step 8
(UHF radios) or “Power Supplies” on page 173 (VHF radios).

Program the radio with the maximum frequency in the radio’s
frequency band: Enter the CCTM command 101 x x 0, where x is the
frequency in hertz.

Enter the CCTM command 72 to determine the lock status in receive
mode. Note the response.
lock status=xyz (x=RF PLL; y=FCL; z=LO2) (0=not in lock; 1=in lock)

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10.

Task 2 —
Lock Status

If the lock status is 111 or 110, the synthesizer is functioning in the
receive mode, and the power supplies and PLL are functioning
correctly. Go to “Loop Filter” on page 187 to check the loop filter,
VCOs, and buffer amplifiers. If the lock status is 011 or 010, the
synthesizer is faulty in the receive mode. Go to “Power Supplies” on
page 173.

A lock error indicates that the frequency synthesizer, FCL or second LO is
out of lock. To determine which is faulty, check the lock status as described
below.
1.

If not already done, place the radio in CCTM.

Program the radio with the receive frequency of a channel that is
known to be out of lock: Enter the CCTM command 101 x x 0,
where x is the frequency in hertz.

Enter the CCTM command 72 to determine the lock status in receive
mode. Note the response. The action required depends on the lock
status as described in the following steps.
lock status=xyz (x=RF PLL; y=FCL; z=LO2) (0=not in lock; 1=in lock)

172

If the lock status is x0x, where x is 0 or 1, the FCL is suspect; go to
“Power Supply for FCL” on page 215.

If the lock status is 011, the synthesizer is suspect, although the power
supplies are functioning correctly; go to “Loop Filter” on page 187.

If the lock status is 010, the synthesizer and second LO are both out
of lock. First investigate the synthesizer, excluding the power supplies;
go to “Loop Filter” on page 187. If necessary, investigate the receiver
later.

If the lock status is 110, the second LO is out of lock. Go to
“Receiver Fault Finding” on page 227.

If the lock status is 111, this implies normal operation. But if the lock
error persists, replace the main-board assembly and go to “Final
Tasks” on page 147.

Frequency Synthesizer Fault Finding

TM9100 Service Manual
© Tait Electronics Limited August 2005

9.2

Power Supplies
First check that a power supply is not the cause of the fault. There are four
power supplies for the frequency synthesizer — two are supplied from the
PSU (power supply unit) module and two are produced in the synthesizer
circuitry itself:

Introduction

■

Task 3: 14 V DC supply from SMPS (VCL SUPPLY)

■

Task 4: 6 V DC supply from 6 V regulator in PSU module (+6V0)

■

Task 5: 5 V DC supply following filtering of 6 V supply (+5V DEC)

■

Task 6: 3 V DC supply from 3 V regulator in PSU module (+3V0 AN)

The measurement points for diagnosing faults in the power supplies are
summarized in Figure 9.1.
Figure 9.1

Measurement points for the frequency synthesizer power supply circuitry

PIN 4 OF
IC606

FREQUENCY
SYNTHESIZER

+6V0
Q500 AND
R533

FILTERING
OF SUPPLY
FOR VCO
CIRCUITRY

FILTERING
OF SUPPLY
FOR PLL
AND LOOP
FILTER

14 V
SMPS

+5V DEC

6V
SUPPLY
PIN 5 OF
IC606

+9V0

9V
SUPPLY

+3V0 AN

3V
SUPPLY

VCL SUPPLY
JUNCTION OF
C531 AND R530

PIN 4 OF
Q508

L506
SIGNAL TYPES
RF
ANALOG

PINS 7 AND 15
OF IC503

CLOCK
DIGITAL

VCO
CIRCUITRY

LOOP
FILTER
AND
SUMMER

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© Tait Electronics Limited August 2005

INVERTER

PLL

AGND

INTERFACE
CIRCUITRY

Frequency Synthesizer Fault Finding

173

Task 3 —
14V Power Supply

First check the output VCL SUPPLY from the SMPS, which is itself provided
with a 9V DC supply from a 9V regulator in the PSU module.
1.

Remove the main-board assembly from the chassis.

Place the radio in CCTM.

Measure the SMPS output VCL SUPPLY at the via between C531 and
R530 (see Figure 9.2).
C531: 14.2 V ± 0.3 DC

If the SMPS output is correct, go to Task 4. If it is not, go to Step 5.

Check the 9 V supply at Q500 and R533 (see Figure 9.3).
Q500 and R533: 9.0 V ± 0.3 DC

If the voltage is correct, go to Step 7. If it is not, the 9V regulator
IC601 is suspect; go to Task 3 of “Power Supply Fault Finding” on
page 158.

Remove the FCL TOP can and check the SMPS circuit based on Q500,
Q502 and L502 (see Figure 9.3).
Remove the SYN BOT can and check IC504 and IC505 for shorts
(see Figure 9.4); replace any suspect IC.

174

If a fault is found, repair the circuit, confirm the removal of the fault,
and go to “Final Tasks” on page 147. If the repair failed or no fault
could be found, replace the main-board assembly and go to “Final
Tasks” on page 147.

Frequency Synthesizer Fault Finding

TM9100 Service Manual
© Tait Electronics Limited August 2005

Figure 9.2

Synthesizer circuitry under the SYN TOP can and the 6 V regulator IC606 (top side)

Pin 5 (5-pin device)

(pin not used)

B1 band
Q512

Q508
Q5004

Measurement
point on L506

H5/H6 bands
Q512

Q508
Q506
Q507

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Figure 9.3

Synthesizer circuitry under the FCL TOP can (top side)

SYN TOP CAN

176

Frequency Synthesizer Fault Finding

TM9100 Service Manual
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Task 4 —
6V Power Supply

If the output of the SMPS is correct, check the 6V DC supply next.
1.

Measure the supply +6V0 at pin 4 of IC606 (see Figure 9.2).
pin 4 of IC606: 6.0 ± 0.3V DC

If the voltage is correct, go to Task 5. If it is not, measure the 9V
input at pin 5 of IC606 (see Figure 9.2).
pin 5 of IC606: 9.0 ± 0.3V DC

If the voltage is correct, go to Step 4. If it is not, the 9V regulator
IC601 is suspect; go to Task 3 of “Power Supply Fault Finding” on
page 158.

If the input to the regulator IC606 is correct but not the output,
check IC606 (see Figure 9.2) and the associated circuitry; if
necessary, replace IC606.
Remove the SYN TOP can and check the C-multipliers Q508 (pins 3,
4, 5) and Q512 for shorts (see Figure 9.2); replace any suspect
transistor.

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Figure 9.4

Synthesizer circuitry under the SYN BOT and VCO BOT cans (bottom side)

B1 band

H5/H6 bands

Q511

Q505

178

Frequency Synthesizer Fault Finding

TM9100 Service Manual
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Task 5 —
5V Power Supply

If the SMPS output and 6V DC supply are correct, check the +5V DEC
supply next.
1.

Remove the SYN TOP can.

Measure the supply +5V DEC at pin 4 of Q508 (see Figure 9.2).
pin 4 of Q508: 5.3 ± 0.3V DC

If the voltage is correct, go to Task 6. If it is not, go to Step 4 (UHF
radios) or Step 5 (VHF radios).

With a UHF radio check for faults in the C-multiplier Q508 (pins 3,
4, 5) and the 5V and transmit-receive switches based on Q506, Q507
and Q508 (pins 1, 2, 6) (see Figure 9.2). Replace any suspect
transistor. Conclude with Step 6.

With a VHF radio check for faults in the C-multiplier and 5V switch
based on Q508 and Q5004 (see Figure 9.2). Remove the VCO BOT
can and check the transmit-receive switch based on Q5002 and
Q5003 (see Figure 9.4). Replace any suspect transistor. Conclude
with Step 6.

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Task 6 —
3V Power Supply

If the SMPS output and the 6V and 5V supplies are correct, the remaining
power supply to check is the 3V DC supply.
1.

Measure the supply +3V0 AN at pins 7 and 15 of IC503
(see Figure 9.2).
pins 7 and 15 of IC503: 2.9 ± 0.3V DC

If the voltage is correct, go to “Phase-locked Loop” on page 181. If it
is not, go to Step 3.

Check the supply at L506 (see Figure 9.2). The measurement point
is the via shown in the figure.
L506: 2.9 ± 0.3V DC

180

If the voltage is correct, go to Step 5. If it is not, the 3 V regulator
IC603 is suspect; go to Task 3 of “Power Supply Fault Finding” on
page 158.

Check the components in the path from L506 to IC503. Also check
IC503; if necessary, replace IC503 (see Figure 9.2).

Frequency Synthesizer Fault Finding

TM9100 Service Manual
© Tait Electronics Limited August 2005

9.3

Phase-locked Loop

Introduction

If there is no fault with the power supplies, check the critical output from,
and inputs to, the PLL:
■

Task 7: supply for charge pump

■

Task 8: reference frequency input

■

Task 9: DIG SYN EN line input

■

Task 10: SYN LOCK line output

The measurement points for diagnosing faults concerning the PLL inputs
and output are summarized in Figure 9.5.
Task 7 —
Supply for
Charge Pump

First check the supply for the charge pump of the PLL.
1.

Measure the supply for the charge pump at pin 16 of IC503
(see Figure 9.2).
pin 16 of IC503: 5.0 ± 0.3 V DC

If the voltage is correct, go to Task 8. If it is not, go to Step 3.

Check the C-multiplier Q512 (see Figure 9.2) and check IC503
itself; if necessary, replace the transistor or IC.

If there is a fault, repair the circuit, confirm the removal of the fault,
and go to “Final Tasks” on page 147. If the repair failed or no fault
could be found, replace the main-board assembly and go to “Final
Tasks” on page 147.

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Frequency Synthesizer Fault Finding

181

182

Frequency Synthesizer Fault Finding

DIGITAL
BOARD

L102

VIA TO CHECK
SYN LOCK

R105

VIA TO CHECK
DIG SYN FAST

R104

VIA TO CHECK
DIG SYN EN

SYN LOCK

DIG SYN FAST

DIG SYN EN

TP503
(JUNCTION OF
R566 AND R570)
INVERTER

COLLECTOR
OF Q505

OUTPUT

PLL

R542

PIN 10 OF
IC503

JUNCTION OF
C541 AND R547

PIN 16 OF
IC503

PLL

R549

SUPPLY FOR CHARGE PUMP

FEEDBACK
VOLTAGE
PIN 6 OF IC505
LOOP
FILTER
AND
SUMMER

OUTPUT OF LOOP
FILTER AT C565

VCO
CIRCUITRY

LOOP
VOLTAGE

PIN 5 OF
IC505

PLL FEEDBACK

REFERENCE
VOLTAGE

FILTERING
OF SUPPLY
FOR PLL
AND LOOP
FILTER

R568

R544

L506

FCL

DIGITAL

CLOCK

ANALOG

SIGNAL TYPES
RF

CDC VCO MOD

SYN CDC LFV

PIN 14 OF
IC503

PIN 8 OF
IC503

C536

REFERENCE
FREQUENCY

FREQUENCY
SYNTHESIZER

+3V0 AN

CODEC
AND AUDIO
CIRCUITRY

3V
SUPPLY

Figure 9.5
Test and measurement points for the synthesizer PLL and loop filter

TM9100 Service Manual
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Figure 9.6

Components between the digital board and the frequency synthesizer

FCL TOP CAN

VIAS FOR
MEASUREMENTS

Task 8 —
Reference
Frequency

If the supply for the charge pump is correct, check the reference frequency
input from the FCL to the PLL.
1.

Measure the reference frequency at pin 8 of IC503 (see Figure 9.2).
pin 8 of IC503: 13.012 ± 0.002 MHz and 1.1 ± 0.2 Vpp

If the signal is correct, go to Task 9. If it is not, go to Step 3.

Check IC503 (see Figure 9.2). Replace IC503 if it is suspect.

Determine if the fault has been removed. If it has, go to “Final Tasks”
on page 147. If it has not, the FCL is suspect; go to “Power Supply
for FCL” on page 215.

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Task 9 —
DIG SYN EN

Line

If the supply for the charge pump and the reference frequency are correct,
check the DIG SYN EN line input.
1.

Check the DIG SYN EN line at pin 10 of IC503 (see Figure 9.2).
Enter the CCTM command 334 0 to switch off the synthesizer, and
measure the voltage at pin 10.
pin 10 of IC503: 0 V DC (after entry of CCTM 334 0)

Enter the command 334 1 to switch on the synthesizer, and measure
the voltage again.
pin 10 of IC503: 2.5 ± 0.3 V DC (after entry of CCTM 334 1)

If the voltages measured in Step 1 and Step 2 are correct, go to
Task 10. If they are not, go to Step 4.

Remove R104 (see Figure 9.6) and repeat the above measurements
as follows:

Enter the CCTM command 334 0 to switch off the synthesizer, and
measure the voltage at the via between R104 (see Figure 9.6) and
the digital board.
via at R104: 0 V DC (after entry of CCTM 334 0)

Enter the CCTM command 334 1 to switch on the synthesizer, and
measure the voltage at the via between R104 (see Figure 9.6) and
the digital board.
via at R104: 3.3 ± 0.3 V DC (after entry of CCTM 334 1)

184

If the voltages measured in Step 5 and Step 6 are still not correct, the
digital board is faulty; replace the main-board assembly and go to
“Final Tasks” on page 147. If the voltages are correct, go to Step 8.

There is a fault between the digital board and IC503. Locate the fault.
Check and resolder R104 in position (see Figure 9.6), and check for
continuity between pin 10 of IC503 (see Figure 9.2) and the digital
board via R104.

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Task 10 —
Line

SYN LOCK

If all the critical inputs to the PLL are correct, check the SYN LOCK line
output.
1.

Enter the CCTM command 72 to determine the lock status in receive
mode. Note the status.
lock status=xyz (x=RF PLL; y=FCL; z=LO2) (0=not in lock; 1=in lock)

Check the SYN LOCK line by measuring the voltage at pin 14 of IC503
(see Figure 9.2). The voltage should depend on the lock status as
follows:
lock status 111 or 110: 3.0 ± 0.3 V DC at pin 14 of IC503
lock status 011 or 010: 0 V DC at pin 14 of IC503

If the voltage measured in Step 2 is correct, go to “Loop Filter” on
page 187. If it is not, go to Step 4.

Check for continuity between pin 14 of IC503 and the digital board
via R568 (see Figure 9.2) and L102 (see Figure 9.6).

If there is a fault, go to Step 6. If there is no fault, the digital board is
faulty; replace the main-board assembly and go to “Final Tasks” on
page 147.

Repair the fault. Confirm the removal of the fault and go to “Final
Tasks” on page 147. If the repair failed or no fault could be found,
replace the main-board assembly and go to “Final Tasks” on
page 147.

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Figure 9.7

Synthesizer circuitry under the SYN TOP can (top side)

B1 band
Q512

Junction of
C541 and R547

H5/H6 bands
Q512

Junction of
C541 and R547

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9.4

Loop Filter

Introduction

If the power supplies for the frequency synthesizer are correct, and the PLL
is functioning properly, check the loop filter next:
■

Task 11: check loop voltage

■

Task 12: VCO fault

■

Task 13: check reference voltage

■

Task 14: check feedback voltage

■

Task 15: check DIG SYN FAST line

■

Task 16: check TP503 test point

The test and measurement points for diagnosing faults concerning the loop
filter are summarized in Figure 9.5.
Task 11 —
Check Loop Voltage

Check whether the loop filter is functioning correctly by measuring the
loop voltage at the output of the filter at C565.
1.

If not already done, remove the main-board assembly from the
chassis, remove the SYN TOP can, and place the radio in CCTM.

Remove R542 (see Figure 9.7).

Using an oscilloscope, proceed as follows to observe the voltage at
C565 before and after grounding the junction between C541 and
R547 (see Figure 9.7):
While holding the oscilloscope probe at C565, use a pair of tweezers
to momentarily ground the junction. The voltage should change to
the following value (if it is not already at this value):
C565: 13.3 ± 0.3 V DC

If the loop voltage is correct, go to Step 5. If it is not, the loop-filter
circuitry is suspect; go to Task 13.

Proceed as follows to observe the voltage at C565 before and after
applying 3 V DC to the junction of C541 and R547; there is a
convenient 3 V level at R544 (see Figure 9.7):
While holding the probe at C565, use the tweezers to momentarily
apply 3 V DC to the junction; do not touch the board with your
hand, and do not allow the tweezers to touch any cans when you
remove them. The voltage should change to:
C565: < 0.5 V DC

If the loop voltage is correct, go to Task 12. If it is not, the loop-filter
circuitry is suspect; go to Task 13.

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Task 12 —
VCO Faulty

If the loop voltage is correct, the loop filter is functioning properly.
The VCO and related circuitry is therefore suspect. The section to proceed
to depends on the type of the radio and the nature of the fault.
1.

With a UHF radio go to Step 2. With a VHF radio go to “VCO and
Related Circuitry (VHF Radios)” on page 206.

If a UHF radio exhibits a lock error or a receive fault. the receive
VCO is suspect; go to “Receive VCO and Related Circuitry (UHF
Radios)” on page 192.
If it exhibits a system error or a transmit fault, the transmit VCO is
suspect; go to “Transmit VCO and Related Circuitry (UHF
Radios)” on page 201.

Task 13 —
Check Reference
Voltage

If the loop-filter circuitry is suspect, first check the reference voltage for the
filter.
1.

Remove the SYN BOT can.

Measure the reference voltage at pin 5 of IC505 (see Figure 9.4).
The result should be:
IC505 pin 5:

188

2.8 ± 0.1 V DC

If the voltage is correct, go to Task 14. If it is not, the referencevoltage circuitry is suspect; go to Step 4.

Resolder R542 in position and check the C-multiplier Q512
(see Figure 9.7).

If a fault is found, repair the circuit, and confirm that the reference
voltage is now correct. If it is, go to “Final Tasks” on page 147. If it
is not, or if no fault could be found, replace the main-board assembly
and go to “Final Tasks” on page 147.

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Task 14 —
Check Feedback
Voltage

If the loop filter is suspect but the reference voltage is correct, check the
feedback voltage.
1.

Measure the feedback voltage at pin 6 of IC505 (see Figure 9.4).
The result should be:
IC505 pin 6:

2.8 ± 0.1 V DC

If the voltage is not correct, the loop filter is faulty; go to Step 3.
If the voltage is correct, resolder R542 in position (see Figure 9.7)
and go to Task 15.

Check IC504, IC505, Q511 (see Figure 9.4), C5085 to C5089 (B1
band, see Figure 9.7) or C5085 and C5086 (H5, H6 bands
see Figure 9.7), and associated components.

If a fault is found, repair the circuit, repeat the measurement of the
feedback voltage in Step 1, and resolder R542 in position
(see Figure 9.7).

If the feedback voltage is now correct, go to “Final Tasks” on
page 147. If it is not, or if no fault could be found, replace the mainboard assembly and go to “Final Tasks” on page 147.

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Task 15 —
Check DIG SYN FAST
Line

If the loop filter is suspect but the reference and feedback voltages are
correct, check the DIG SYN FAST line, which is input to the inverter.
1.

Enter the CCTM command 389 1 to set the synthesizer mode to fast.

Measure the voltage at the collector of Q505 (see Figure 9.4).
The result should be:
Q505 collector: 14.2 ± 0.3 V DC (after entry of CCTM 389 1)

Enter the CCTM command 389 0 to set the mode to slow.

Measure the voltage at the collector of Q505 (see Figure 9.4).
The result should be:
Q505 collector: 0 V DC (after entry of CCTM 389 0)

If the voltages measured in Step 2 and Step 4 are correct, go to
Task 16. If they are not, go to Step 6.

Remove R105 (see Figure 9.6).

Enter the CCTM command 389 1 to set the mode to fast.

Measure the voltage at the via between R105 and the digital board
(see Figure 9.6). The result should be:
via at R105: 0 V DC (after entry of CCTM 389 1)

Enter the CCTM command 389 0 to set the mode to slow.

10.

Measure the voltage at the via between R105 and the digital board
(see Figure 9.6). The result should be:
via at R105: 3.3 ± 0.3 V DC (after entry of CCTM 389 0)

190

11.

If the voltages measured in Step 8 and Step 10 are correct, go to
Step 12. If they are not, the digital board is faulty; replace the mainboard assembly and go to “Final Tasks” on page 147.

12.

Check and resolder R105 in position (see Figure 9.6), and check for
continuity between the collector of Q505 (see Figure 9.4) and the
digital board via R105.

13.

If a fault is found, repair the circuit, and confirm that the voltages are
now correct. If they are, go to “Final Tasks” on page 147. If they are
not, or if no fault could be found, replace the main-board assembly
and go to “Final Tasks” on page 147.

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Task 16 —
Check TP503 Test
Point

If the reference voltage, feedback voltage, and DIG SYN FAST line are all
correct, check the voltage at the TP503 test point.
1.

Measure the voltage at the TP503 test point (see Figure 9.7).
The oscilloscope should show a DC level less than 3.0V with no sign
of noise or modulation.
TP503 test point: < 3.0 V DC

If the correct result is obtained, go to Step 3. If it is not, go to Step 4.

The loop filter is faulty but the above measurements do not provide
more specific information. Check IC504, IC505, Q511
(see Figure 9.4), C5085 to C5089 (B1 band, see Figure 9.7) or
C5085 and C5086 (H5, H6 bands see Figure 9.7), and associated
components. Conclude with Step 9.

Remove R566 and R570 (see Figure 9.7), which provide a
modulation path to the VCO(s).

Repeat the measurement of Step 1.

If the correct result is now obtained, go to Step 7. If the correct result
is still not obtained, the CODEC and audio circuitry is suspect;
resolder R566 and R570 in position (see Figure 9.7), and go to
“CODEC and Audio Fault Finding” on page 371.

Resolder R566 and R570 in position (see Figure 9.7).

Check IC504 (pins 6, 8, 9) (see Figure 9.4) and the associated
components in the loop filter.

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9.5

Receive VCO and Related Circuitry (UHF Radios)
If there is no fault with the power supplies, the PLL inputs and output, and
the loop filter, check the VCO and related circuitry. The procedures in this
section apply only to UHF radios with a lock error or receive fault, and
therefore with suspect receive VCO and related circuitry. (The minimum
and maximum receive frequencies for the different UHF frequency bands
are defined in Table 9.2.) There are six aspects:

Introduction

■

Task 17: check receive VCO

■

Task 18: repair PLL feedback

■

Task 19: repair receive VCO

■

Task 20: check switching to receive mode

■

Task 21: repair switching network

■

Task 22: check receive buffer amplifier

The measurement points for diagnosing faults in the VCO and related
circuitry are summarized in Figure 9.8.
Table 9.2

Minimum and maximum receive frequencies for the different UHF frequency bands

Frequency band

Receive frequency in MHz
Minimum

Maximum

337 ± 5

441 ± 5

378 ± 5

498 ± 5

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RX PORT

SYN RX LO1

TX PORT

DIGITAL
BOARD

VIA TO CHECK
DIG SYN TR SW

RECEIVER

TRANSMITTER

SYN TX LO

DIGITAL

CLOCK

ANALOG

SIGNAL TYPES
RF

R103

PIN 4 OF
IC5100

BASE OF
Q5100

DIG SYN EN

DIG SYN TR SW

RECEIVE
BUFFER
AMPLIFIER
AND
COUPLER

TRANSMIT
BUFFER
AMPLIFIER
AND
COUPLER

PIN 6 OF
Q506

R585

R593

PIN 3 OF
Q506

LOOP
FILTER
AND
SUMMER

INVERTER

JUNCTION OF
C541 AND R547

5 V SWITCH

FILTERING
OF SUPPLY
FOR VCO
CIRCUITRY

Q508 AND
R593

+5V DEC

TR SWITCH

R577

RECEIVE
VCO

LOOP VOLTAGE

FREQUENCY SYNTHESIZER

TRANSMIT VCO

PIN 6 OF
Q5001

PLL FEEDBACK

PLL

R544

L506

+3V0 AN

3V
SUPPLY

Figure 9.8
Measurement points for the VCO and related circuitry in UHF radios

Frequency Synthesizer Fault Finding

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Task 17 —
Check Receive VCO

Check that the correct receive frequency is synthesized. This is the
frequency of the receive VCO output SYN RX LO1 at the RX port shown in
Figure 9.9.
1.

Enter the CCTM command 335 0 to set the transmit-receive switch
off (receive mode).

Using a frequency counter, proceed as follows to observe the receive
frequency at the RX port before and after grounding the junction
between C541 and R547 (see Figure 9.9):
While holding the probe from the counter on the RX port, use a pair
of tweezers to momentarily ground the junction. The frequency
should change to:
RX port: maximum receive frequency (see Table 9.2)

The loop filter will hold its output steady at 13.3 V. This should result
in a frequency equal to the maximum given in Table 9.2.
3.

If the receive frequency measured in Step 2 is correct, go to Step 4.
If it is incorrect, go to Task 19, but if no frequency is detected, go to
Task 20.

Proceed as follows to observe the receive frequency at the RX port
before and after applying 3 V DC to the junction of C541 and R547;
there is a convenient 3 V level at R544 (see Figure 9.9):
While holding the probe on the RX port, use the tweezers to
momentarily apply 3 V DC to the junction; do not touch the board
with your hand, and do not allow the tweezers to touch any cans
when you remove them. The frequency should change to:
RX port: minimum receive frequency (see Table 9.2)

The loop filter will hold its output steady at about 0V. This should
result in a frequency equal to the minimum given in Table 9.2.
5.

194

If the receive frequency measured in Step 4 is correct, go to Task 18.
If it is incorrect, go to Task 19. If no frequency is detected, go to
Task 20.

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Figure 9.9

Synthesizer circuitry under the SYN TOP and VCO TOP cans (UHF radio, top side)
Q507

Q506

Tx port

Q508

Junction of
C541 and R547

Rx port

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Task 18 —
Repair PLL feedback

If both the minimum and maximum receive frequencies are correct, the
PLL feedback is suspect.
1.

Resolder R542 in position (see Figure 9.9).

Remove the VCO BOT can.

Replace the components C567, R574 (see Figure 9.10) and IC503
(see Figure 9.9).

Also check the second stage of the receive buffer amplifier based on
IC5100 (see Figure 9.10). Repair any fault.

Confirm that the fault in the radio has been removed. If it has, go to
“Final Tasks” on page 147. If it has not, replace the main-board
assembly and go to “Final Tasks” on page 147.

Figure 9.10

Synthesizer circuitry under the VCO BOT can
(UHF radio, bottom side)
Q5001

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Task 19 —
Repair Receive VCO

If either or both the minimum and maximum receive frequencies are
incorrect, the receive VCO circuitry is faulty.
1.

Remove the VCO TOP can.

Check the receive VCO. The circuitry is based on Q504
(see Figure 9.9).

If a fault is found, repair it and go to Step 4. If no fault is found, go
to Step 6.

Repeat the frequency measurements in Step 2 and Step 4 of Task 17.

If the frequencies are now correct, resolder R542 in position
(see Figure 9.9), and go to “Final Tasks” on page 147. If they are
still not correct, go to Step 6.

Resolder R542 in position (see Figure 9.9). Replace the mainboard assembly and go to “Final Tasks” on page 147.

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Task 20 —
Check Switching
to Receive Mode

If no receive frequency is detected in the check of the receive VCO, first
check that the transmit-receive switch is functioning correctly.
1.

Resolder R542 in position (see Figure 9.9).

Enter the CCTM command 335 0 to switch on the supply to the
receive VCO.

Measure the voltage at the first collector (pin 3) of Q506
(see Figure 9.9). The voltage should be:
pin 3 of Q506: 5.0 ± 0.3 V DC (after entry of CCTM 335 0)

Enter the CCTM command 335 1 to switch off the supply.

Again measure the voltage at the first collector of Q506.
pin 3 of Q506: 0 V DC (after entry of CCTM 335 1)

198

If the voltages measured in Step 3 and Step 5 are correct, go to
Task 22. If they are not, the switching network is suspect; go to
Task 21.

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Task 21 —
Repair Switching
Network

If the transmit-receive switch is not functioning correctly, first check the DIG
SYN TR SW line to confirm that the digital board is not the cause. If the digital
board is not faulty, the switching network is suspect.
1.

Enter the CCTM command 335 0 to set the transmit-receive switch
off (receive mode). Measure the voltage on the DIG SYN TR SW line
between Q508 and R593 (see Figure 9.9).
R593: 0 V DC (after entry of CCTM 335 0)

Enter the CCTM command 335 1 to set the transmit-receive switch
on (transmit mode). Again measure the voltage at R593.
R593: 2.0 ± 0.5 V DC (after entry of CCTM 335 1)

If the voltages measured in Step 1 and Step 2 are correct, go to
Step 9. If they are not, remove R103 (see Figure 9.6) and go to
Step 4.

Enter the CCTM command 335 0 and measure the voltage at the via
between R103 and the digital board (see Figure 9.6).
via at R103: 0 V DC (after entry of CCTM 335 0)

Enter the CCTM command 335 1 and again measure the voltage at
the via between R103 and the digital board.
via at R103: 3.3 ± 0.3 V DC (after entry of CCTM 335 1)

If the voltages measured in Step 4 and Step 5 are correct, go to
Step 7. If they are not, the digital board is faulty; resolder R103 in
position (see Figure 9.6), replace the main-board assembly and go to
“Final Tasks” on page 147.

Check and resolder R103 in position (see Figure 9.6), and check for
continuity between Q508 and the digital board via R593
(see Figure 9.9) and R103.

If no fault is found, go to Step 9. If a fault is found, repair the circuit,
confirm that the voltages are now correct, and go to “Final Tasks” on
page 147. If the repair failed, replace the main-board assembly and go
to “Final Tasks” on page 147.

Check the circuitry for the transmit-receive and 5V switches (based
on Q506, Q507 and Q508) (see Figure 9.9).

10.

If a fault is found, repair the circuit, confirm that the voltages are now
correct, and go to “Final Tasks” on page 147. If the repair failed or
the fault could not be found, replace the main-board assembly and go
to “Final Tasks” on page 147.

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Task 22 —
Check Receive
Buffer Amplifier

If no receive frequency is detected but the switching network is not faulty,
check the receive buffer amplifier. If the amplifier is not faulty, there might
be a fault in the receive VCO that was not detected earlier.
1.

Remove the VCO BOT can.

Check the receive buffer amplifier in receive mode: Enter the CCTM
command 335 0 to set the transmit-receive switch off.

Measure the voltages at the base of Q5100 and at pin 4 of IC5100
(see Figure 9.10).
base of Q5100: 0.7 ± 0.1V DC (receive mode)
pin 4 of IC5100: 2.0 ± 0.5V DC (receive mode)

Then check the receive buffer amplifier in transmit mode: Enter the
CCTM command 335 1 to set the transmit-receive switch on.

Again measure the voltages of Q5100 and IC5100.
base of Q5100: 0V DC (transmit mode)
pin 4 of IC5100: 0V DC (transmit mode)

200

If the voltages are correct, the receive VCO is suspect; go to Step 7.
If they are not, the receive buffer amplifier is suspect; go to Step 9.

Remove the VCO TOP can.

Check the receive VCO circuitry based on Q504 (see Figure 9.9).
Conclude with Step 10.

Check the first buffer stage (based on Q5100) and the second stage
(based on IC5100) (see Figure 9.10).

10.

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9.6

Transmit VCO and Related Circuitry (UHF Radios)
If there is no fault with the power supplies, the PLL inputs and output, and
the loop filter, check the VCO and related circuitry. The procedures in this
section apply only to UHF radios with a system error or transmit fault, and
therefore with suspect transmit VCO and related circuitry. (The minimum
and maximum transmit frequencies for the different UHF frequency bands
are defined in Table 9.3.) There are five aspects:

Introduction

■

Task 23: check transmit VCO

■

Task 24: repair PLL feedback

■

Task 25: repair transmit VCO

■

Task 26: check switching to transmit mode

■

Task 27: check transmit buffer amplifier

The measurement points for diagnosing faults in the VCO and related
circuitry are summarized in Figure 9.8.
Table 9.3

Minimum and maximum transmit frequencies for the different UHF frequency bands

Frequency band

Transmit frequency in MHz
Minimum

Maximum

371 ± 5

492 ± 5

419 ± 5

545 ± 5

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Task 23 —
Check Transmit VCO

Check that the correct transmit frequency is synthesized. This is the
frequency of the transmit VCO output SYN TX LO at the TX port shown in
Figure 9.9.
1.

Enter the CCTM command 335 1 to set the transmit-receive switch
on (transmit mode).

Using a frequency counter, proceed as follows to observe the transmit
frequency at the TX port before and after grounding the junction
between C541 and R547 (see Figure 9.9):
While holding the probe from the counter on the TX port, use a pair
of tweezers to momentarily ground the junction. The frequency
should change to:
TX port: maximum transmit frequency (see Table 9.3)

The loop filter will hold its output steady at 13.3 V. This should result
in a frequency equal to the maximum given in Table 9.3.
3.

If the transmit frequency measured in Step 2 is correct, go to Step 4.
If it is incorrect, go to Task 25. If no frequency is detected, go to
Task 26.

Proceed as follows to observe the transmit frequency at the TX port
before and after applying 3 V DC to the junction of C541 and R547;
there is a convenient 3 V level at R544 (see Figure 9.9):
While holding the probe on the TX port, use the tweezers to
momentarily apply 3 V DC to the junction; do not touch the board
with your hand, and do not allow the tweezers to touch any cans
when you remove them. The frequency should change to:
TX port: minimum transmit frequency (see Table 9.3)

The loop filter will hold its output steady at about 0V. This should
result in a frequency equal to the minimum given in Table 9.3.
5.

202

If the transmit frequency measured in Step 4 is correct, go to Task 24.
If it is incorrect, go to Task 25. If no frequency is detected, go to
Task 26.

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Task 24 —
Repair PLL feedback

Task 25 —
Repair Transmit
VCO

If both the minimum and maximum transmit frequencies are correct, the
PLL feedback is suspect.
1.

Resolder R542 in position (see Figure 9.9).

Remove the VCO BOT can.

Replace the components C570, R578 (see Figure 9.10) and IC503
(see Figure 9.9).

Confirm that the fault in the radio has been removed. If it has, go to
“Final Tasks” on page 147. If it has not, replace the main-board
assembly and go to “Final Tasks” on page 147.

If either or both the minimum and maximum transmit frequencies are
incorrect, the transmit VCO circuitry is faulty.
1.

Remove the VCO TOP can.

Check the transmit VCO. The circuitry is based on Q510
(see Figure 9.9).

If a fault is found, repair it and go to Step 4. If no fault is found, go
to Step 6.

Repeat the frequency measurements in Step 2 and Step 4 of Task 23.

If the frequencies are now correct, resolder R542 in position
(see Figure 9.9), and go to “Final Tasks” on page 147. If they are
still not correct, go to Step 6.

Resolder R542 in position (see Figure 9.9). Replace the mainboard assembly and go to “Final Tasks” on page 147.

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Task 26 —
Check Switching
to Transmit Mode

If no transmit frequency is detected in the check of the transmit VCO, first
check that the transmit-receive switch is functioning correctly.
1.

Resolder R542 in position (see Figure 9.9).

Enter the CCTM command 335 1 to switch on the supply to the
transmit VCO.

Measure the voltage at the second collector (pin 6) of Q506
(see Figure 9.9). The voltage should be:
pin 6 of Q506: 5.0 ± 0.3 V DC (after entry of CCTM 335 1)

Enter the CCTM command 335 0 to switch off the supply.

Again measure the voltage at the second collector of Q506.
pin 6 of Q506: 0 V DC (after entry of CCTM 335 0)

204

If the voltages measured in Step 2 and Step 4 are correct, go to
Task 27. If they are not, the switching network is suspect; go to
Task 21.

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Task 27 —
Check Transmit
Buffer Amplifier

If no transmit frequency is detected but the switching network is not faulty,
check the transmit buffer amplifier. If the amplifier is not faulty, there might
be a fault in the transmit VCO that was not detected earlier.
1.

Remove the VCO BOT can.

Check the transmit buffer amplifier in receive mode: Enter the
CCTM command 335 0 to set the transmit-receive switch off.

Measure the voltage at pin 6 of Q5001 (see Figure 9.10).
pin 6 of Q5001: 0 V DC (receive mode)

Then check the transmit buffer amplifier in transmit mode: Enter the
CCTM command 335 1 to set the transmit-receive switch on.

Again measure the voltage at Q5001.
pin 6 of Q5001: 0.7 ± 0.1 V DC (transmit mode)

If the voltages are correct, the transmit VCO is suspect; go to Step 7.
If they are not, the transmit buffer amplifier is suspect; go to Step 9.

Remove the VCO TOP can.

Check the transmit VCO circuitry based on Q510 (see Figure 9.9).
Conclude with Step 10.

Check the buffer circuitry based on Q5001 (see Figure 9.10).

10.

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9.7

VCO and Related Circuitry (VHF Radios)
If there is no fault with the power supplies, the PLL inputs and output, and
the loop filter, check the VCO and related circuitry. The procedures in this
section apply only to VHF radios; the VHF frequency bands are defined in
Table 9.4. There are six aspects:

Introduction

■

Task 28: check VCO

■

Task 29: repair PLL feedback

■

Task 30: repair VCO

■

Task 31: check transmit-receive switch

■

Task 32: repair switching network

■

Task 33: check buffer amplifier

The measurement points for diagnosing faults in the VCO and related
circuitry are summarized in Figure 9.11.
Table 9.4

Minimum and maximum frequencies for the different VHF frequency bands

Frequency band

Frequency in MHz
Minimum

206

84 ± 5

Frequency Synthesizer Fault Finding

Maximum
200 ± 5

TM9100 Service Manual
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DIGITAL
BOARD

SYN RX LO1

RECEIVER

VIA TO CHECK
DIG SYN TR SW

RX PORT

SYN TX LO

TRANSMITTER

TX PORT

R103

PIN 3 OF
Q5003

D5004

+5V DEC

BUFFER
AMPLIFIER
AND
COUPLER

PIN 2 OF
Q5001

VCO

FREQUENCY SYNTHESIZER

PIN 2 OF
D5004

DIG SYN EN

DIG SYN TR SW

TR SWITCH

PIN 1 OF
D5004

PLL FEEDBACK

INVERTER

5 V SWITCH

FILTERING
OF SUPPLY
FOR VCO
CIRCUITRY

LOOP
FILTER
AND
SUMMER

JUNCTION OF
C541 AND R547

PLL

R544

3V
SUPPLY

DIGITAL

CLOCK

ANALOG

SIGNAL TYPES
RF

L506

+3V0 AN

Figure 9.11
Measurement points for the VCO and related circuitry in VHF radios

Frequency Synthesizer Fault Finding

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Task 28 —
Check VCO

Check that the correct receive and transmit frequencies are synthesized.
The receive frequency is that of the VCO output SYN RX LO1 at the RX port
shown in Figure 9.12. The transmit frequency is that of the output SYN TX LO
at the TX port.
1.

Enter the CCTM command 335 1 to set the transmit-receive switch
on (transmit mode).

Using a frequency counter, proceed as follows to observe the transmit
frequency at the TX port before and after grounding the junction
between C541 and R547 (see Figure 9.12):
While holding the probe from the counter on the TX port, use a pair
of tweezers to momentarily ground the junction. The frequency
should change to:
TX port: maximum VCO frequency (see Table 9.4)

The loop filter will hold its output steady at 13.3 V. This should result
in a frequency equal to the maximum given in Table 9.4.
3.

If the maximum frequency measured in Step 2 is correct, go to
Step 4. If it is incorrect, go to Task 30, but if no frequency at all is
detected, go to Task 31.

Enter the CCTM command 335 0 to set the transmit-receive switch
off (receive mode).

The loop filter will hold its output steady at about 0V. This should
result in a frequency equal to the minimum given in Table 9.4.
6.

208

If the minimum frequency measured in Step 5 is correct, go to
Task 29. If it is incorrect, go to Task 30. If no frequency is detected,
go to Task 31.

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Figure 9.12

Synthesizer circuitry under the SYN TOP can (VHF radio, top side)
Tx port

Junction of
C541 and R547

Rx port

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If both the maximum and minimum VCO frequencies are correct, then the
PLL feedback is suspect.

Task 29 —
Repair PLL feedback

Figure 9.13

Resolder R542 in position (see Figure 9.12).

Remove the VCO BOT can.

Replace the components L510 (see Figure 9.13) and IC503
(see Figure 9.12).

Confirm that the fault in the radio has been removed. If it has, go to
“Final Tasks” on page 147. If it has not, replace the main-board
assembly and go to “Final Tasks” on page 147.

Synthesizer circuitry under the VCO BOT can (VHF radio, bottom side)

VCO BOT

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Task 30 —
Repair VCO

If either or both the maximum and minimum frequencies are incorrect, the
VCO circuitry is faulty.
1.

Remove the VCO BOT can.

Check the VCO. The circuitry is based on Q5000
(see Figure 9.13).

If a fault is found, repair it and go to Step 4. If no fault is found, go
to Step 7.

Repeat Step 1 and Step 2 of Task 28 to measure the maximum VCO
frequency.

Repeat Step 4 and Step 5 of Task 28 to measure the minimum VCO
frequency.

If the frequencies are now correct, resolder R542 in position
(see Figure 9.12), and go to “Final Tasks” on page 147. If they are
still not correct, go to Step 7.

Resolder R542 in position (see Figure 9.12). Replace the mainboard assembly and go to “Final Tasks” on page 147.

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Task 31 —
Check TransmitReceive Switch

If no frequency is detected in the check of the VCO, first check that the
transmit-receive switch is functioning correctly.
1.

Resolder R542 in position (see Figure 9.12).

Remove the VCO BOT can.

Enter the CCTM command 335 0 to switch on the supply to the RX
port.

Measure the voltage at pin 2 of D5004 (see Figure 9.13). (Some RF
noise might be observed.) The voltage should be:
pin 2 of D5004: 5.0 ± 0.3 V DC (after entry of CCTM 335 0)

Enter the CCTM command 335 1 to switch off the supply.

Again measure the voltage at pin 2 of D5004.
pin 2 of D5004: 0 V DC (after entry of CCTM 335 1)

If the voltages measured in Step 4 and Step 6 are correct, go to
Step 8. If they are not, the switching network is suspect; go to
Task 32.

Enter the CCTM command 335 1 to switch on the supply to the TX
port.

Measure the voltage at pin 1 of D5004 (see Figure 9.13). (Some RF
noise might be observed.) The voltage should be:
pin 1 of D5004: 5.0 ± 0.3 V DC (after entry of CCTM 335 1)

10.

Enter the CCTM command 335 0 to switch off the supply.

11.

Again measure the voltage at pin 1 of D5004.
pin 1 of D5004: 2.1 ± 0.4 V DC (after entry of CCTM 335 0)

12.

212

If the voltages measured in Step 9 and Step 11 are correct, go to
Task 33. If they are not, the switching network is suspect; go to
Task 32.

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Task 32 —
Repair Switching
Network

Enter the CCTM command 335 0 to set the transmit-receive switch
off (receive mode). Measure the voltage on the DIG SYN TR SW line at
pin 3 of Q5003 (see Figure 9.13).
pin 3 of Q5003: 5.0 ± 0.3 V DC (after entry of CCTM 335 0)

Enter the CCTM command 335 1 to set the transmit-receive switch
on (transmit mode). Again measure the voltage at Q5003.
pin 3 of Q5003: 0 V DC (after entry of CCTM 335 1)

If the voltages measured in Step 1 and Step 2 are correct, go to
Step 9. If they are not, remove R103 (see Figure 9.6) and go to
Step 4.

Enter the CCTM command 335 0 and measure the voltage at the via
between R103 and the digital board (see Figure 9.6).
via at R103: 3.3 ± 0.3 V DC (after entry of CCTM 335 0)

Enter the CCTM command 335 1 and again measure the voltage at
the via between R103 and the digital board.
via at R103: 0 V DC (after entry of CCTM 335 1)

Check and resolder R103 in position (see Figure 9.6), and check for
continuity between Q5003 (see Figure 9.13) and the digital board
via R103.

Check the circuitry for the transmit-receive and 5V switches (based
on Q5002 and Q5003) (see Figure 9.13).

10.

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Task 33 —
Check Buffer
Amplifier

If no VCO frequency is detected but the switching network is not faulty,
check the buffer amplifier. If the amplifier is not faulty, there might be a fault
in the VCO that was not detected earlier.
1.

Enter the CCTM command 335 0 to set the transmit-receive switch
off.

Measure the voltage at pin 3 of D5004 (see Figure 9.13). (Some RF
noise might be observed.)
pin 3 of D5004: 4.2 ± 0.2 V DC

Measure the voltage at pin 1 of Q5001 (see Figure 9.13).
pin 1 of Q5001: 0.7 ± 0.2 V DC

214

If the voltages measured in Step 2 and Step 3 are not correct, go to
Step 5. If they are, check the VCO circuitry based on Q5000
(see Figure 9.13). Conclude with Step 6.

The buffer amplifier is suspect. Check the buffer circuitry (based on
Q5001) (see Figure 9.13).

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9.8

Power Supply for FCL

Fault-Diagnosis
Stages

Indications of a fault in the FCL will have been revealed by the initial checks
in “Initial Checks” on page 170 and the PLL checks in “Phase-locked
Loop” on page 181. In the latter case a fault with the reference frequency
input from the FCL to the PLL will imply that the FCL is suspect. Fault
diagnosis of the FCL is divided into four stages:
■

check power supply

■

check VCXO and TCXO outputs

■

check signals at TP501 and TP502

■

check VCXO and CODEC circuitry

The checking of the power supply is given in this section in Task 34 below.
The remaining three stages are covered in “VCXO and TCXO Outputs”
to “VCXO and CODEC Circuitry” respectively. The test and
measurement points for diagnosing faults in the FCL are summarized in
Figure 9.14.

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216

Frequency Synthesizer Fault Finding
C536

SUPPLY

+3V0 AN

RECEIVER

SYN RX OSC

AGND

VCXO OUTPUT
AT C536

INTERFACE
CIRCUITRY

PLL

PSU

TP504

C510

TCXO OUTPUT

R541

VCXO OUTPUT
AT R522
(PIN 1 OF IC501)

TP500

LOOP
VOLTAGE

BUFFER AMPLIFIER

TCXO

VCXO

MIXER

TP502

TP501

SYN DIG FREF

SYN CDC FCL

DIFFERENCE
FREQUENCY

CDC VCXO MOD

FEEDBACK
SIGNAL

FCL CIRCUITRY

LO INPUT
AT R521
(PIN 4 OF IC501)

LPF

MODULATOR
BUFFER
AMPLIFIER

DIGITAL

CLOCK

ANALOG

SIGNAL TYPES

ADC

CODEC 2

DAC

DIGITAL
BOARD

Figure 9.14
Test and measurement points the FCL circuitry

TM9100 Service Manual
© Tait Electronics Limited August 2005

Task 34 —
Power Supply

If the FCL is suspect, first check that the 3V power supply is not the cause
of the fault.
1.

If not already done, remove the main-board assembly from the chassis
and place the radio in CCTM.

Measure the supply +3V0 AN at the via shown in Figure 9.15. The via
is adjacent to the CDC TOP can.
via adjacent to CDC TOP can: 3.0 ± 0.3 V DC

Figure 9.15

If the voltage is correct, go to “VCXO and TCXO Outputs” on
page 218. If it is not, the 3V regulator IC603 is suspect; go to Task 3
of “Power Supply Fault Finding” on page 158.

TCXO circuitry under the CDC TOP can
VIA FOR MEASURING 3 V DC SUPPLY

IF TOP CAN

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9.9

VCXO and TCXO Outputs

Task 35 —
VCXO Output

If the 3V power supply is not faulty, check the VCXO output as follows:
1.

Use an oscilloscope probe to check the VCXO output at C536 —
probe the via next to C536 (see Figure 9.16). The signal should be:
VCXO output at C536: sine wave of 1.1 ± 0.2 Vpp on 1.4 ± 0.2 V DC

218

If the signal is correct, go to Task 36. If it is not, go to Step 3.

The VCXO circuitry under the VCXO BOT can is faulty. Remove the
VCXO BOT can.

Locate and repair the fault in the VCXO (Q501, Q503, XL501 and
associated components) (see Figure 9.17).

Confirm the removal of the fault and go to Task 36. If the repair
failed, replace the main-board assembly and go to “Final Tasks” on
page 147.

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Figure 9.16

FCL circuitry under and adjacent the FCL TOP can
VIA FOR MEASURING VCXO OUTPUT

POSITION IN WHICH TO PLACE R527
FOR FAULT-DIAGNOSIS PURPOSES
WHEN LOOP OSCILLATES

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Task 36 —
TCXO Output

If the VCXO output is correct, check the TCXO output as follows:
1.

Use the oscilloscope probe to check the TCXO output at the TP504
test point (see Figure 9.16). The signal is SYN RX OSC and should be:
TCXO output at TP504 test point: clipped sine wave of 1.0 ± 0.2 Vpp

Figure 9.17

If the signal is correct, go to “Signals at TP501 and TP502” on
page 221. If it is not, go to Step 3.

The TCXO circuitry under the CDC TOP can is faulty. Remove the
CDC TOP can.

Locate and repair the fault in the TCXO (XL500 and associated
components) (see Figure 9.15).

Confirm the removal of the fault and go to “Signals at TP501 and
TP502” on page 221. If the repair failed, replace the main-board
assembly and go to “Final Tasks” on page 147.

FCL circuitry under the VCXO BOT can

SYN BOT CAN

CAN FOR
DIGITAL
BOARD

CDC BOT CAN

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9.10

Signals at TP501 and TP502

Introduction

If the VCXO and TCXO outputs are correct, the next stage is to check the
signals at the TP501 and TP502 test points. The procedure is divided into
three tasks:
■

Task 37: check signal at TP502

■

Task 38: check signal at TP501 and ground TP501 if loop is oscillating

■

Task 39: check signal at TP502 with TP501 grounded

These checks will reveal any faults in the mixer and LPF circuitry, and any
additional fault in the VCXO circuitry.
Task 37 —
TP502 Test Point

Check the signal at the TP502 test point to determine if there is a fault in the
mixer or LPF (low-pass filter) circuitry:
1.

Use the oscilloscope probe to check the difference frequency at the
TP502 test point (see Figure 9.16). The signal is SYN CDC FCL and
should be:
TP502 test point: sine wave of 1.1 ± 0.2 Vpp on 1.5 ± 0.1 V DC

If the signal is correct, go to Task 38. If it is not, go to Step 3.

The mixer or LPF circuitry under the FCL TOP can is faulty. Remove
the FCL TOP can.

Locate the fault in the mixer (IC501 and associated components) or
LPF circuitry (IC502 pins 5 to 7, and associated components)
(see Figure 9.16).

Repair the circuitry. Note that the TCXO input to the mixer at
R521 (pin 4 of IC501) (see Figure 9.16) should be:
TCXO input at R521: square wave with frequency of 13000000 Hz
and amplitude of 3.0 ± 0.2 Vpp

Also, the VCXO input to the mixer at R522 (pin 1 of IC501)
(see Figure 9.16), although noisy and difficult to measure, should be:
VCXO input at R522: sine wave of 20 ± 10 mVpp

Confirm the removal of the fault and go to Task 38. If the repair
failed, replace the main-board assembly and go to “Final Tasks” on
page 147.

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Task 38 —
TP501 Test Point

If the signal at the TP502 test point is correct, check the signal at the TP501
test point:
1.

With the oscilloscope probe at the TP501 test point
(see Figure 9.16), check the DAC output CDC VCXO MOD. If a
triangular wave is present, go to Step 2. Otherwise go to “VCXO and
CODEC Circuitry” on page 224.

A fault is causing the loop to oscillate. If not already done, remove the
FCL TOP can.

Check the waveform at the TP500 test point (see Figure 9.16).
The waveform should be an amplified and inverted version of the
waveform at the TP501 test point.

If the waveform is correct, go to Step 5. If it is not, there is a fault in
the modulator buffer amplifier (IC502 pins 1 to 3, and associated
components) (see Figure 9.16). Rectify the fault and return to
Step 1.

Connect the TP501 test point to ground by resoldering R527 in the
position shown in Figure 9.16. This forces the VCXO loop voltage
high.

Use the oscilloscope probe to check the VCXO output at C536 —
probe the via next to C536 (see Figure 9.16). The signal should be:
VCXO output at C536: sine wave with frequency of 13.017 MHz and
amplitude of 1.1 ± 0.2 Vpp on 1.4 ± 0.2 V DC

222

If the signal is correct, go to Task 39. If it is not, go to Step 8.

The VCXO circuitry is faulty. If not already done, remove the VCXO
BOT can.

Locate and repair the fault in the VCXO circuitry (Q501, Q503,
XL501 and associated components) (see Figure 9.17).

10.

Confirm the removal of the fault, and go to Task 39. If the repair
failed, replace the main-board assembly and go to “Final Tasks” on
page 147.

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Task 39 —
TP502 Test Point
(TP501 Grounded)

If the loop was oscillating, Task 38 will have revealed any fault in the
VCXO circuitry. If there was no fault, or if the circuit was repaired, a check
at the TP502 test point is now required. This will show if there are any
additional faults in the mixer or LPF circuitry.
1.

Use the oscilloscope probe to check the difference frequency at the
TP502 test point (see Figure 9.16). The signal is SYN CDC FCL and
should be:
TP502 test point: sine wave with frequency of at least 15 kHz and
amplitude of 1.1 ± 0.2 Vpp on 1.5 ± 0.1 V DC

If the signal is correct, go to Step 6. If it is not, go to Step 3.

The mixer circuitry (IC501 and associated components) or the LPF
circuitry (IC502 pins 5 to 7, and associated components) under the
FCL TOP can is faulty (see Figure 9.16). Locate the fault.

Also, the VCXO input to the mixer at R522 (pin 1 of IC501)
(see Figure 9.16), although noisy and difficult to measure, should be:
VCXO input at R522: sine wave of 20 ± 10 mVpp

Confirm the removal of the fault, and go to Step 6. If the repair
failed, resolder R527 in its original position as shown in Figure 9.16,
replace the main-board assembly and go to “Final Tasks” on
page 147.

Resolder R527 in its original position as shown in Figure 9.16.

Replace all cans.

If the signal is correct, the fault has been removed; go to “Final
Tasks” on page 147. If the signal is not correct, the repair failed;
replace the main-board assembly and go to “Final Tasks” on
page 147.

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9.11

VCXO and CODEC Circuitry

Introduction

If the signals at the TP501 and TP502 test points are correct, two CCTM
checks will reveal any remaining faults. These possible faults concern the
VCXO tank circuit and the CODEC 2 circuitry. There are therefore three
aspects, which are covered in Task 40 to Task 42:
■

Task 40: CCTM checks

■

Task 41: VCXO tank circuit

■

Task 42: CODEC 2 circuitry

Following any repairs of the VCXO or CODEC 2 circuitry, Task 40 will
need to be repeated to confirm the removal of the fault.
Task 40 —
CCTM Checks

If the signals at the TP501 and TP502 test points are correct, or any related
faults were rectified, perform the following CCTM checks:
1.

Enter the CCTM command 393 1 1900. Measure the voltage level at
the TP501 test point (see Figure 9.16):
TP501 test point: 1.3 ± 0.2 V DC (after CCTM 393 1 1900)

Enter the CCTM command 72 and note the lock status.
lock status=xyz (x=RF PLL; y=FCL; z=LO2) (0=not in lock; 1=in lock)

Enter the CCTM command 393 1 –1900. Again measure the voltage
level at the TP501 test point:
TP501 test point: 2.1 ± 0.2 V DC (after CCTM 393 1 –1900)

Enter the CCTM command 72 and note the lock status.

If the above voltage levels are not correct or if the FCL is out of lock
in either or both of the above cases, investigate the VCXO tank
circuit; go to Task 41.
If the voltage level remains fixed at about 1.5V DC, investigate the
CODEC 2 circuitry; go to Task 42.
If the voltage levels are all correct (following earlier repairs), the fault
has been removed; go to “Final Tasks” on page 147.

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Task 41 —
VCXO Tank Circuit

If the CCTM checks indicate that the VCXO tank circuit is faulty, repair
the circuit as follows:
1.

If not already done, remove the VCXO BOT can.

Locate and repair the fault in the VCXO tank circuit (Q501, D501,
D502, XL501 and associated components) (see Figure 9.17).

Confirm the removal of the fault and go to Step 4. If the repair failed,
replace the main-board assembly and go to “Final Tasks” on page 147.

Replace all cans.

Repeat Task 40 to confirm the removal of the fault. If the repair
failed, replace the main-board assembly and go to “Final Tasks” on
page 147.

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Task 42 —
CODEC 2 Circuitry

If the CCTM checks indicate a fault in the CODEC 2 circuitry or with the
digital signals to and from the circuitry, rectify the fault as follows:
1.

Most of the CODEC 2 circuitry is situated under the CDC TOP can.
If not already done, remove the CDC TOP can.

Check the following digital signals at IC205 (see Figure 9.15):
■

pin 10 : DIG CDC2 LRCK

■

pin 12 : DIG CDC2 SCLK

■

pin 8 : CDC2 DIG SDTO

■

pin 9 : DIG CDC2 SDTI

These signals to and from the digital board should all be active:
digital signals: 3.3 ± 0.3 V

If the digital signals are correct, the CODEC 2 circuitry is suspect;
go to Step 6. If they are not, go to Step 4.

If any or all digital signals are missing, check the connections between
IC205 and the digital board (see Figure 9.15).

If there are faults such as open circuits in the connections, repair the
circuitry and repeat Task 40.
If the connections are not faulty, then the digital board is faulty.
Replace the main-board assembly and go to “Final Tasks” on
page 147.

226

The CODEC 2 circuitry comprises IC205 and associated
components under the CDC TOP can (see Figure 9.15) as well as R246
under the CDC BOT can (see Figure 7.3 on page 158). Locate the
fault.

Repair the circuitry. Note that, if the circuitry is functioning properly,
probing the TP501 test point (see Figure 9.16) during power-up
will show a five-step staircase signal followed by a random nine-step
staircase signal — this is the expected power-up auto-calibration
sequence.

Confirm the removal of the fault, and go to Step 9. If the repair
failed, replace the main-board assembly and go to “Final Tasks” on
page 147.

Replace all cans.

10.

Repeat Task 40 to confirm the removal of the fault. If the repair
failed, replace the main-board assembly and go to “Final Tasks” on
page 147.

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Receiver Fault Finding

Fault Conditions

This section covers the diagnosis of faults in the receiver. The fault-diagnosis
procedures consist of 18 tasks grouped into the following sections.
The symptoms of the fault in the receiver circuitry determine which
sections are relevant:
■

“Faulty Receiver Sensitivity”

■

“Excessive Loss of Sensitivity”

■

“Moderate or Slight Loss of Sensitivity”

■

“Incorrect RSSI Readings”

■

“Faulty Radio Mute”

■

“High Receiver Distortion”

If the receiver sensitivity is low, begin with “Faulty Receiver Sensitivity” on
page 228 to determine the extent of the loss in sensitivity.
CCTM Commands

Table 10.1
Command
72
101 x y 0
376
378

The CCTM commands required are listed in Table 10.1. Full details of the
commands are given in “Computer-Controlled Test Mode (CCTM)” on
page 112.

CCTM commands required for the diagnosis of faults in the receiver
Description
Read lock status of RF PLL, FCL and LO2 — displays xyz (0=not in lock, 1=in lock)
Set transmit frequency (x in hertz) and receive frequency (y in hertz) to specified values
Read tuning voltage for front-end circuitry — displays voltage x in millivolts
Read signal power at output of channel filter — displays power x (square of amplitude)

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10.1

Faulty Receiver Sensitivity

Introduction

This section covers the determination of the extent of the receiver’s loss of
sensitivity. Depending on the nature of the fault, a reduction in receiver
sensitivity of 1dB is often due to a reduction in receiver gain of many
decibels. It is therefore easier to measure gain loss rather than sensitivity loss.
Consequently, if the receiver sensitivity is too low, first check the receiver
gain. The procedure is given in Task 1 below.

Task 1 —
Determine Extent
of Sensitivity Loss

Determine the receiver gain as follows. The corresponding loss of sensitivity
can then be deduced. Depending on the extent of the loss, continue with
“Excessive Loss of Sensitivity” on page 230 or “Moderate or Slight Loss of
Sensitivity” on page 234 to rectify the fault.
1.

Input an RF signal (not necessarily modulated) of –90 dBm (or –84
dBm with a trigger-base radio) at the RF connector.

Enter the CCTM command 378 to measure the receiver output level.

Note the value x returned for the receiver output level. Depending
on the frequency band in which the radio operates, the value should
be:
receiver output level x: normally between 500 000 and 6000 000

Note that a change in the input level of 10mdB should result in a tenfold change in x.
4.

If necessary, measure the RF voltage at the QN test point
(see Figure 10.1). (There is access through a hole in the IF TOP can.)
For comparison, the voltages corresponding to the above values of x
are:
x = 500 000: 12mVpp
x = 6000 000: 120mVpp

With an unmodulated RF signal the frequency should be 64.000kHz,
provided that the LO1, FCL and LO2 are locked and on the correct
frequency.
5.

228

Receiver Fault Finding

Given the value of x, go to the relevant section as follows:
■

x < 1500, go to “Excessive Loss of Sensitivity” on page 230
(sensitivity is very low)

■

x < 500 000, go to “Moderate or Slight Loss of Sensitivity” on
page 234 (sensitivity is low)

TM9100 Service Manual
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Figure 10.1

Receiver circuitry under the IF TOP can (top side)

B1 band

Q404

Measurement point

Q404

Measurement point

H5/H6 bands

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229

10.2

Excessive Loss of Sensitivity

Introduction

This section covers the case where the receiver has suffered an excessive loss
of sensitivity. As measured in Task 1, the receiver gain will be less than 1500,
which implies a sensitivity that is more than 40mdB too low. The faultdiagnosis procedure for this case consists of five tasks:
■

Task 2: check power supplies

■

Task 3: check logic signal

■

Task 4: check lock status

■

Task 5: check biasing of IF amplifier

■

Task 6: check matching circuitry

If the fault does not lie with the power supplies, it is probably in the control,
LO, IF1 or IF2 circuitry.
Task 2 —
Check Power
Supplies

First check the two power supplies 3V0 AN and 3V0 RX for the receiver
circuitry.
1.

Remove the main-board assembly from the chassis.

Check for 3.0V DC (3V0 AN) at the TP601 test point near the LO2 BOT
can (see Figure 10.2).
TP601 test point: 3.0V DC

If the voltage is correct, go to Step 4. If it is not, the 3V regulator
IC603 is suspect; go to Task 3 of “Power Supply Fault Finding” on
page 158.

Remove the LO2 BOT can.

Check for 3.0V DC (3V0 RX) around the collector feed to Q402 or
Q403 of LO2 (see Figure 10.2).
Q402 or Q403 collector: 3.0V DC

Alternative measurement points are the collector feed to Q401 of the
RF LNA under the FE TOP can (see Figure 10.3) or Q404 of the IF
amplifier under the IF TOP can (see Figure 10.1).
6.

230

Receiver Fault Finding

If the voltage is correct, go to Task 3. If it is not, the 3V RX switch
(based on Q604 and Q605) in the PSU module is suspect; go to
Task 3 of “Power Supply Fault Finding” on page 158.

TM9100 Service Manual
© Tait Electronics Limited August 2005

Figure 10.2

Receiver circuitry under the LO2 BOT can (bottom side)

B1 band

H5/H6 bands

Figure 10.3

Receiver circuitry under the FE TOP can (top side)
Q401

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Measurement point

Receiver Fault Finding

231

Task 3 —
Check Logic Signal

If there is no fault with the power supplies, check the logic signal DIG RX EN
that is input from the digital board.
1.

Check the logic signal DIG RX EN at pin 8 of IC403 (see Figure 10.2).
The signal is active high. The required status is active.
pin 8 of IC403: about 3.0V (active)

An alternative measurement point to the above is pin 24 of IC400
under the IF TOP can (see Figure 10.1).

Task 4 —
Check Lock Status

If DIG RX EN is active, go to Task 4. If it is not, go to Step 3.

Check the signal continuity from the digital board to the receiver.
Repair any fault and go to Step 4. If the digital board itself appears to
be faulty, replace the main-board assembly and go to “Final Tasks” on
page 147.

Recalibrate the receiver using the calibration application.

Confirm the removal of the fault and go to “Final Tasks” on
page 147. If the repair failed, go to Task 7.

If the logic signal from the digital board is active, as required, check the lock
status of the radio.
1.

Enter the CCTM command 72 to determine the lock status.
The status should be normal:
lock status: 111 (LO1, FCL, LO2 all in lock)

232

If the lock status is normal, go to Task 5. If the LO1 is not in lock, go
to “Frequency Synthesizer Fault Finding” on page 169. If the FCL is
not in lock, go to “Power Supply for FCL” on page 215. If the LO2
is not in lock, go to Step 3.

Check the components around IC403, Q402 and Q403
(see Figure 10.2). Repair any fault.

Recalibrate the receiver using the calibration application.

Confirm the removal of the fault, and go to “Final Tasks” on
page 147. If the repair failed go to Task 7.

Receiver Fault Finding

TM9100 Service Manual
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Task 5 —
Check Biasing
of IF Amplifier

If the lock status is normal, check the biasing of the IF amplifier.
1.

Remove the IF TOP can.

Check all components around Q404 of the IF amplifier
(see Figure 10.1).

Check the 3V supply voltage at L419; use the measurement point
shown in Figure 10.1.

Also check the amplifier bias conditions. First measure Vc between
the collector of Q404 and ground (see Figure 10.1).
Vc: 2.0 ± 0.2V

Secondly, check Ic. To do so, unsolder and raise one terminal of L419
(tombstone position) (see Figure 10.1), connect a multimeter
between this terminal and the pad for the terminal, and measure the
current.
Ic: 1.8 ± 0.5mA

Task 6 —
Check Matching
Circuitry

If the checks in Step 2 to Step 5 reveal no fault, go to Task 6. If there
is a fault, repair it and go to Step 7.

Recalibrate the receiver using the calibration application.

Confirm the removal of the fault, and go to “Final Tasks” on
page 147. If the repair failed go to Task 7.

Having excluded the IF amplifier, check the matching circuitry for the
crystal filters.
1.

Check all remaining components between T401 and IC400 — these
form the matching circuitry for the crystal filters XF400 and XF401
(see Figure 10.1).

If the above check reveals no fault, go to Step 3. If there is a fault,
repair it and go to Step 6.

Remove the PIN TOP and LPF TOP cans.

Make a visual check of the components in the receive path of the PIN
switch and LPF circuits.

If the visual check reveals an obvious fault, repair it and go to Step 6.
If there is no obvious fault, go to Task 7.

Recalibrate the receiver using the calibration application.

Confirm the removal of the fault, and go to “Final Tasks” on
page 147. If the repair failed go to Task 7.

TM9100 Service Manual
© Tait Electronics Limited August 2005

Receiver Fault Finding

233

10.3

Moderate or Slight Loss of Sensitivity

Introduction

This section covers the case where the receiver has suffered a moderate or
slight loss of sensitivity. As measured in Task 1, the receiver gain will be less
than 500 000, but not as low as 1500. With a gain less than 40 000, the loss
of sensitivity will be moderate — about 15mdB too low; otherwise it will
be slight — just a few decibels too low. There are three tasks:
■

Task 7: front-end calibration and tuning voltages

■

Task 8: moderately low receiver sensitivity

■

Task 9: slightly low receiver sensitivity

The fault-diagnosis procedures of Task 8 and Task 9 are similar; although
the differences are minor they are important.
Task 7 —
Front-end
Calibration
and Tuning Voltages

If the loss of sensitivity is moderate or slight, the fault is probably in the
front-end tuning circuitry.
1.

Using the calibration application, check the calibration of the frontend tuning circuitry: Open the “Raw Data” page and click the
“Receiver” tab.

Record the values listed in the “Rx FE Tune BPF Settings” field — these
are the DAC values of the FE (front-end) tuning voltages for the five
frequencies FE TUNE0 to FE TUNE4.
(FE TUNE0 is the lowest frequency and FE TUNE4 the highest frequency in the radio’s frequency band; the values are given in
Table 10.2.)

For each of the frequencies FE TUNE0 to FE TUNE4 in turn, carry out
the following procedure: Enter the CCTM command 101 a a 0,
where a is the frequency in hertz.
Enter the CCTM command 376 and record the value returned — this
is the front-end tuning voltage in millivolts.

234

Compare the values measured in Step 2 and Step 3 with the nominal
DAC and voltage values listed in Table 10.2.

If the DAC and voltage values are correct, go to Step 8. If they are
not, go to Step 6.

Recalibrate the receiver using the calibration application, and check
the DAC and voltage values again.

If the DAC and voltage values are now correct, the fault has been
rectified; go to “Final Tasks” on page 147. If they are not, go to
Step 8.

Go to Task 8 if the receiver output level x measured in Task 1 was less
than 40 000; otherwise go to Task 9.

Receiver Fault Finding

TM9100 Service Manual
© Tait Electronics Limited August 2005

Task 8 —
Moderately Low
Sensitivity

Following the initial investigation in Task 7, check the circuitry as follows
when the sensitivity loss is moderate.
1.

Remove the FE TOP can and, if not already done, the IF TOP can.

Check the soldering of all the components of the front-end tuning
circuitry from C400 to T401 (see Figure 10.1 and Figure 10.3).

Check the 3V supply voltage at L404; use the measurement point
shown in Figure 10.3.

Also check the LNA bias conditions. First measure Vc between the
collector of Q401 and ground (see Figure 10.3).
Vc: 2.7 ± 0.1V

Secondly, check Ic. To do so, unsolder and raise one terminal of L404
(tombstone position) (see Figure 10.3), connect a multimeter
between this terminal and the pad for the terminal, and measure the
current.
Ic: 10 ± 1mA

Table 10.2

If the checks in Step 2 to Step 5 reveal no fault, go to Step 7. If there
is a fault, repair it and go to Step 8.

Check the signal level at the output of LO1 and continue the fault
diagnosis as in “Power Supply for FCL” on page 215.

Recalibrate the receiver using the calibration application.

Confirm the removal of the fault and go to “Final Tasks” on
page 147. If the repair failed, go to Task 9.

Front-end tuning voltages and corresponding DAC values
Tuning voltages at five different frequencies

Frequency band
FE TUNE0

FE TUNE1

FE TUNE2

FE TUNE3

FE TUNE4

B1 band
Frequency (MHz)
DAC value
Voltage (V)

135.9
145.1
155.1
164.1
174.1
37 ± 20
88 ± 15
136 ± 15
174 ± 15
210 ± 15
0.44 ± 0.24 1.04 ± 0.18 1.60 ± 0.18 2.04 ± 0.18 2.57 ± 0.18

H5 band
Frequency (MHz)
DAC value
Voltage (V)

399.9
0 to 36
0 to 0.43

H6 band
Frequency (MHz)
DAC value
Voltage (V)

449.9
470.1
490.1
510.1
530.1
41 ± 20
91 ± 15
134 ± 15
176 ± 15
210 ± 15
0.48 ± 0.24 1.07 ± 0.18 1.58 ± 0.18 2.07 ± 0.18 2.47 ± 0.18

TM9100 Service Manual
© Tait Electronics Limited August 2005

417.1
435.1
452.1
470.1
94 ± 15
106 ± 15
156 ± 15
191 ± 15
1.11 ± 0.18 1.25 ± 0.18 1.84 ± 0.18 2.25 ± 0.18

Receiver Fault Finding

235

Task 9 —
Slightly Low
Sensitivity

236

Following the initial investigation in Task 7, check the circuitry as follows
when the sensitivity loss is slight.
1.

Remove the FE TOP can and, if not already done, the IF TOP can.

Check the soldering of all the components of the front-end tuning
circuitry from C400 to T401 (see Figure 10.1 and Figure 10.3).

Check the IF-amplifier bias conditions as in Step 4 and Step 5 of
Task 5.

Check the LNA bias conditions as in Step 4 and Step 5 of Task 8.

If the checks of Step 2 to Step 4 reveal no fault, go to Step 6. If there
is a fault, repair it and go to Step 7.

Check the PIN switch and LPF as in Task 31 to Task 33 of
“Transmitter Fault Finding (50W/40W Radios)” on page 245 or
“Transmitter Fault Finding (25W Radios)” on page 315.

Recalibrate the receiver using the calibration application.

Confirm the removal of the fault and go to “Final Tasks” on
page 147. If the repair failed, replace the main-board assembly and go
to “Final Tasks” on page 147.

Receiver Fault Finding

TM9100 Service Manual
© Tait Electronics Limited August 2005

10.4

Incorrect RSSI Readings

Introduction

If the RSSI readings are incorrect, the receiver calibration is suspect.
There are four tasks, which cover the four types of settings concerned:
■

Task 10: AGC voltage calibration

■

Task 11: FE tune BPF settings

■

Task 12: RSSI delta gain

■

Task 13: AGC delta gain

If the receiver is properly calibrated but the fault persists, then the receiver
sensitivity is suspect.
Task 10 —
AGC Voltage
Calibration

Table 10.3

The first settings to check concern the AGC voltage calibration.
1.

In the calibration application open the “Raw Data” page and click the
“Receiver” tab.

Note the settings listed in the “AGC Voltage Cal Pts” field. The nominal
settings should be as listed in Table 10.3.

If the settings are correct, go to Task 11. If they are not, go to Step 4.

Recalibrate the receiver and check the settings again.

If the settings are now correct, go to Step 6. If they are not, go to
Task 1 and check the receiver sensitivity.

Check if the RSSI fault has been removed. If it has, go to “Final
Tasks” on page 147. If it has not, go to Task 11.

Nominal AGC data
AGC voltage (mV)

Parameter
B1 band
AGC0
AGC1
AGC2

1725 ± 40
1850 ± 40
2000 ± 50
AGC voltage (mV)
H5 band

AGC0
AGC1
AGC2

1860 ± 40
2040 ± 40
2200 ± 50

H6 band
1870 ± 40
2050 ± 40
2220 ± 50
Receiver input power (dBm)

Standard radio
AGC0
AGC1
AGC2

TM9100 Service Manual
© Tait Electronics Limited August 2005

–50
–60
–68

Trigger-base radio
–44
–54
–62

Receiver Fault Finding

237

Task 11 —
FE Tune BPF Settings

Task 12 —
RSSI Delta Gain

Task 13 —
AGC Delta Gain

238

If the AGC voltage calibration is correct, check the FE tune BPF settings.
1.

Note the settings listed in the “FE Tune BPF Settings” field.
The nominal settings should be as listed in Table 10.2.

If the settings are correct, go to Task 12. If they are not, go to Step 3.

Recalibrate the receiver and check the settings again.

If the settings are now correct, go to Step 5. If they are not, go to
Task 1 of “Faulty Receiver Sensitivity” on page 228 and check the
receiver sensitivity.

Check if the RSSI fault has been removed. If it has, go to “Final
Tasks” on page 147. If it has not, go to Task 12.

If the FE tune BPF settings are also correct, check the RSSI delta gain
values.
1.

Note the values listed in the “Rx Delta Gain Values” field. The values
should be between 0mdB and about –3mdB.

If the values are as expected, go to Task 13. If they are not, go to
Step 3.

Recalibrate the receiver and check the values again.

If the values are now correct, go to Step 5. If they are not, go to
Task 1 and check the receiver sensitivity.

Check if the RSSI fault has been removed. If it has, go to “Final
Tasks” on page 147. If it has not, go to Task 13.

If the RSSI delta gain values are also correct, check the AGC delta gain
values.
1.

Note the values listed in the “AGC Delta Gain Values” field. The values
should run gradually from 0mdB to about 35mdB.

If the values are as expected, go to Step 6. If they are not, go to
Step 3.

Recalibrate the receiver and check the values again.

If the values are now correct, go to Step 5. If they are not, go to
Task 1 and check the receiver sensitivity.

Check if the RSSI fault has been removed. If it has, go to “Final
Tasks” on page 147. If it has not, go to Step 6.

In this case all the RSSI calibration settings are correct, but there is
still an RSSI fault. Go to Task 1 and check the receiver sensitivity.

Receiver Fault Finding

TM9100 Service Manual
© Tait Electronics Limited August 2005

10.5

Faulty Radio Mute

Introduction

If the radio mute is faulty, the calibration settings are suspect. There are three
tasks:
■

Task 14: determine type of muting selected

■

Task 15: noise muting selected

■

Task 16: RSSI muting selected

The programming application is required for Task 14, and the calibration
application for Task 15 and Task 16.
Task 14 —
Determine Type of
Muting Selected

First use the programming application to determine the type of muting
selected.
1.

In the programming application click the “Basic Settings” page under
the “Channel Profiles” heading.

Click the “General Settings” tab.

Check the setting in the “Squelch Detect Type” field. Ensure that the
setting is what the Customer expects.

If the setting is “Noise Level”, implying that noise muting is selected,
go to Task 15. If the setting is “Signal Strength”, implying that RSSI
muting is selected, go to Task 16.

TM9100 Service Manual
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Receiver Fault Finding

239

Task 15 —
Noise Muting
Selected

Table 10.4

With noise muting selected, check the noise mute settings:
1.

In the calibration application open the “Deviation/Squelch” page and
click the “Squelch and Signaling Thresholds” tab.

Ensure that, under the “Squelch Thresholds” label, the settings in the
“Country”, “City” and “Hard” fields are what the Customer expects.

Open the “Raw Data” page and click the “Mute” tab.

Compare the values in the “Mute Noise Readings” field with the
required minimum and maximum values listed in Table 10.4.

If the mute noise readings are correct, go to Task 1 and check the
receiver sensitivity. If they are not, go to Step 6.

Recalibrate the mute and then check if the mute fault has been
removed.

If the fault has been removed, go to “Final Tasks” on page 147. If it
has not, go to Task 1 and check the receiver sensitivity.

Mute data
Mute noise readings

Channel spacing

SINAD (dB)
Minimum noise value

Narrow (12.5 kHz)

Medium (20 kHz)

Wide (25 kHz)

240

Maximum noise value

1900

2300

250

500

3700

4200

1000

1500

5500

7300

2200

3700

Receiver Fault Finding

TM9100 Service Manual
© Tait Electronics Limited August 2005

Task 16 —
RSSI Muting
Selected

Figure 10.4

With RSSI muting selected, check the RSSI mute settings.
1.

In the calibration application open the “Deviation/Squelch” page and
click the “Squelch and Signaling Thresholds” tab.

Check that the values in the “Opening Pt” fields and the “Hysteresis”
fields under the “Squelch Thresholds” label are what the Customer
expects.

If the calibration values are as expected, go to Task 10 and check the
RSSI calibration. If they are not, go to Step 4.

Adjust the values in the “Opening Pt” and “Hysteresis” fields. Program
the radio with the new values.

Check if the mute fault has been removed. If it has, go to “Final
Tasks” on page 147. If it has not, go to Task 10 and check the RSSI
calibration.

TCXO circuitry under the CDC TOP can (top side)

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Receiver Fault Finding

241

10.6

High Receiver Distortion

Introduction

If there is high receiver distortion, the TCXO is suspect, or alternatively, the
matching circuitry for the crystal filters XF400 and XF401. There are two
tasks:
■

Task 17: TCXO calibration and repair of TCXO

■

Task 18: second IF and repair of matching circuitry

Recalibrating the TCXO might often be sufficient to rectify the fault.
Task 17 —
TCXO Calibration
and Repair of TCXO

First check the TCXO calibration and, if necessary, repair the TCXO.
1.

Use the calibration application to check the TCXO calibration:
Open the “Raw Data” page and click the “Volt Ref/TCXO/VCO/VCXO”
tab.

Note the values listed in the “Tx TCXO” and “Rx TCXO” fields of the
“TCXO” group box. The values should be:
Tx TCXO and Rx TCXO values: between +20Hz and –20Hz

242

If the calibration values are correct, go to Step 4. If they are not,
recalibrate the TCXO and go to Step 8.

Remove the CDC TOP can.

Check the components of the TCXO, which is based on XL500
(see Figure 10.4). Repair any fault.

Recalibrate the TCXO and check the TCXO calibration values
again as in Step 1 and Step 2.

If the calibration values are now correct, go to Step 8. If they are not,
go to Task 18.

Check if the distortion fault has been removed. If it has, go to “Final
Tasks” on page 147. If it has not, go to Task 18.

Receiver Fault Finding

TM9100 Service Manual
© Tait Electronics Limited August 2005

Task 18 —
Second IF and
Repair of Matching
Circuitry

If the TCXO is not faulty, check the second IF and, if necessary, repair the
matching circuitry.
1.

Input a large unmodulated RF input signal exceeding –90dBm at the
RF connector.

Use a needle probe to measure the frequency of the signal at the QN
test point — access is through the hole in the IF TOP can
(see Figure 10.1). The frequency is the second IF and should be:
frequency at QN test point: 64.000kHz

If the second IF is correct, go to Step 6. If it is not, go to Step 4.

Recalibrate the TCXO.

Check if the distortion fault has been removed. If it has, go to “Final
Tasks” on page 147. If it has not, go to Step 6.

Remove the IF TOP can.

Check the components between T401 and IC400 — these form the
matching circuitry for the crystal filters XF400 and XF401
(see Figure 10.1).

Repair any fault, confirm the removal of the fault, and go to “Final
Tasks” on page 147. If the repair failed or no fault could be found,
replace the main-board assembly and go to “Final Tasks” on
page 147.

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© Tait Electronics Limited August 2005

Receiver Fault Finding

243

244

Receiver Fault Finding

TM9100 Service Manual
© Tait Electronics Limited August 2005

Transmitter Fault Finding
(50W/40W Radios)

Introduction

This section covers the diagnosis of faults in the transmitter circuitry of the
50W/40W radios. The main indication of a fault in the transmitter is a
reduction in range. This implies that the power output is wrong or too low.
Another type of fault is manifested when the radio always transmits at full
power, even if set otherwise. Regardless of the fault, the lock status should
be normal.

Fault-Diagnosis
Tasks

The procedure for diagnosing transmitter faults is divided into tasks, which
are grouped into the following sections:
■

“Power Supplies”

■

“Transmitter RF Power”

■

“Biasing of PA Driver and PAs”

■

“RF Signal Path”

Before beginning the fault diagnosis with “Power Supplies”, note the
following information regarding CCTM commands, frequency bands, can
removal and replacement, and transmit tests.
CCTM Commands

Table 11.1
Command

The CCTM commands required in this section are listed in Table 11.1.
Full details of the commands are given in “Computer-Controlled Test
Mode (CCTM)” on page 112.

CCTM commands required for the diagnosis of faults in the transmitter
Description

32
33
47
101 x y 0
114 x

Set radio in receive mode
Set radio in transmit mode
Read temperature near PAs — displays temperature x in degrees celsius and voltage y
Set transmit frequency (x in hertz) and receive frequency (y in hertz) to specified values
Set DAC value x (in range 0 to 1023) of transmit power

304
304 x
318
319
326 x

Read clamp current at gate of PA driver — displays DAC value x (in range 0 to 255)
Set DAC value x (in range 0 to 255) of clamp current at gate of PA driver
Read forward-power level — displays corresponding voltage x in millivolts
Read reverse-power level — displays corresponding voltage x in millivolts
Set transmitter power level x (0=off, 1=very low, 2=low, 3=medium, 4=high, 5=maximum)

331
331 x
332
332 x
334 x
335 x

Read bias voltage for first PA — displays DAC value x (in range 0 to 255)
Set DAC value x (in range 0 to 255) of bias voltage for first PA
Read bias voltage for second PA — displays DAC value x (in range 0 to 255)
Set DAC value x (in range 0 to 255) of bias voltage for second PA
Set synthesizer on (x=1) or off (x=0) via DIG SYN EN line
Set transmit-receive switch on (x=1) or off (x=0) via DIG SYN TR SW line

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Transmitter Fault Finding (50W/40W Radios)

245

Frequency Bands

Some fault-diagnosis tasks require programming the radio with the lowest,
center or highest frequency in the radio’s frequency band. The relevant
frequencies for the different bands are listed in Table 11.2. Note that the
following frequency ranges are reserved worldwide for use by distress
beacons:
■

B1 band: 156.8MHz ± 375kHz

■

H5 band: 406.0 to 406.1MHz

Do not program the radio with any frequency in the above ranges.
Table 11.2
Band
B1
H5
H7

Can Removal

Lowest, center and highest frequencies in MHz
Lowest
frequency
136
400
450

Center
frequency
155
435
485

Highest
frequency
174
470
520

There are five cans shielding the bulk of the transmitter circuitry:
■

PAD TOP

■

PAF TOP

■

DIRC TOP

■

PIN TOP

■

LPF TOP

To remove any can, first remove the main-board assembly from the chassis.
In the case of the PAD TOP and PAF TOP cans, first detach the heat-transfer
block from the main board. Secure the block again after removing the cans.
Follow the procedures given in “Disassembly and Reassembly” on
page 123.
Can Replacement

246

Replace all cans that have been removed only after repairing the board.
An exception is the B1 band, however, where the LPF TOP can must be in
place if the transmitter is to operate correctly.

Transmitter Fault Finding (50W/40W Radios)

TM9100 Service Manual
© Tait Electronics Limited August 2005

Transmit Tests

The following points need to be borne in mind when carrying out transmit
tests:
■

secure main-board assembly

■

ensure proper antenna load

■

limit duration of transmit tests

■

protect against accidental transmissions

■

avoid thermal and RF burns

These points are discussed in more detail below.
Secure Main-Board
Assembly

Before conducting any transmit tests, ensure that the main-board assembly
is adequately secured in the chassis. This is essential if overheating of the
radio is to be avoided. (As mentioned earlier, the heat-transfer block must
already be secured to the main board of the assembly.) It is good practice to
secure the assembly by at least the two external screws and one of the
internal screws. The screws are labelled I and E in Figure 5.3 on page 127.
There is no need, however, to secure the lid of the radio body.

Ensure Proper
Antenna Load

The radio has been designed to operate with a 50Ω termination impedance,
but will tolerate a wide range of antenna loading conditions. Nevertheless,
care should be exercised. Normally the RF connector on the main-board
assembly will be connected to the RF communications test set as shown in
Figure 4.2 on page 106. But for those tests where this connection is not
necessary, a 50Ω load may be used instead. Do not operate the transmitter
without such a load or without a connection to the test set. Failure to do so
might result in damage to the power output stage of the transmitter.

Limit Duration of
Transmit Tests

After setting the frequency and power level (if necessary), enter the CCTM
command 33 to perform a transmit test. This command places the radio in
transmit mode. After completing the measurement or check required,
immediately enter the CCTM command 32. This command returns the
radio to the receive mode. Restricting the duration of transmit tests in this
way will further limit the danger of overheating. The reason for this
precaution is that the transmit timers do not function in the CCTM mode.

Protect Against
Accidental
Transmissions

Under certain circumstances the microprocessor can key on the transmitter.
Ensure that all instruments are protected at all times from such accidental
transmissions.

Avoid Thermal
and RF Burns

Avoid thermal burns. Do not touch the cooling fins or underside of the
radio body when the transmitter is or has been operating. Avoid RF burns.
Do not touch the antenna or the RF signal path on the circuit board while
the transmitter is operating.

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Transmitter Fault Finding (50W/40W Radios)

247

11.1

Power Supplies
First check that a power supply is not the cause of the fault. There are two
power supplies and a switch circuit for the transmitter:

Introduction

■

Task 1: 13.8V DC supply from power connector (+13V8 BATT)

■

Task 2: switch circuit for 13.8V DC supply

■

Task 3: 9V DC supply from 9V regulator in PSU module (+9V0 TX)

The measurement and test points for diagnosing faults in the power supplies
are summarized in Figure 11.1.
Figure 11.1

Measurement and test points for diagnosing faults involving the power supplies for
the transmitter

+9V0 TX

TRANSMITTER
+13.8 V DC
+13.8 V DC SUPPLY
SUPPLY TO PAs
TO PA DRIVER

POWER
SUPPLY

9V0 TX
TEST POINT

+13V8 BATT
SIGNAL TYPES
RF
SWITCH

ANALOG

AGND
L310

L306
GND
TEST POINT

OTHER
TRANSMITTER
CIRCUITRY

248

PAs

DRIVER

EXCITER

Transmitter Fault Finding (50W/40W Radios)

INTERFACE
CIRCUITRY

FREQUENCY
SYNTHESIZER

TM9100 Service Manual
© Tait Electronics Limited August 2005

Task 1 —
13.8V Power Supply

First check the power supply from the power connector.
1.

Obtain a needle probe to use for measurements of the power supply
at the PA driver and PAs. If none is available, remove the PAF TOP and
PAD TOP cans.

Set the DC power supply to 13.8V, with a current limit of 10A.

Program the radio with the highest frequency in the radio’s frequency
band: Enter the CCTM command 101 x x 0, where x is the frequency
in hertz. The required values for the different frequency bands are
given in Table 11.2.

Enter the CCTM command 326 5 to set the radio to maximum
power.

Attempt to place the radio in transmit mode. Enter the CCTM
command 33.

If the radio enters the transmit mode, continue with Step 7. If instead
a C03 error is displayed in response to the command 33, go to Task 7
in “Transmitter RF Power” on page 262.

Measure the voltage at the point on L310 shown in Figure 11.2
(B1 band) or Figure 11.3 (H5, H7 bands). This is the supply at the
common drain of Q309 and Q310, and should be:
common drain of Q309 and Q310: more than 13V DC

Also measure the voltage at the point on L306 shown in Figure 11.4
(B1 band) or Figure 11.5 (H5, H7 bands). This is the supply at the
drain of Q306, and should be:
drain of Q306: more than 13V DC

Enter the CCTM command 32 to place the radio in receive mode.

10.

If the power supply measured in Step 7 and Step 8 is not correct, go
to Task 2. If it is, go to Task 3.

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Figure 11.2

Point for measuring the power supply to the PAs (B1 band)
MEASUREMENT POINT ON L310

L310

PAF TOP

Q310

Q309

B1 BAND

250

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Figure 11.3

Point for measuring the power supply to the PAs (H5 and H7 bands)
MEASUREMENT POINT ON L310

L310

PAF TOP

Q310

Q309

H5, H7 BANDS

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Figure 11.4

Point for measuring the power supply to the PA driver (B1 band)
POINT 2 ON R350

MEASUREMENT
POINT ON R339

Q308

R339

L306

R350

PAD TOP

MEASUREMENT
POINT ON L306

POINT 1 ON R350

Q306

B1 BAND

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Figure 11.5

Point for measuring the power supply to the PA driver (H5 and H7 bands)
POINT 2 ON R 350

MEASUREMENT
POINT ON R339

Q308

R339

MEASUREMENT
POINT ON L306

L306

R350

PAD TOP

POINT 1 ON R350

Q306

H5, H7 BANDS

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Task 2 —
Check Switch Circuit

If the power supply to the drains of the PAs and PA driver is not correct, the
switch circuit is suspect. Check the circuit as follows:
1.

Measure the voltage at the point 1 on R350 shown in Figure 11.4
(B1 band) or Figure 11.5 (H5, H7 bands). The voltage should be:
point 1 on R350: 13.8V DC

If the voltage measured in Step 1 is correct, go to Step 3. If it is not,
check for continuity between R350 and the power connector. Repair
any fault and conclude with Step 8.

Measure the voltage at R339 as shown in Figure 11.4 (B1 band) or
Figure 11.5 (H5, H7 bands). The voltage should be:
R339: 9V DC

If the voltage measured in Step 3 is correct, go to Step 5. If it is not,
go to Task 3 and check the 9V power supply.

Measure the voltage at the point 2 on R350 shown in Figure 11.4
(B1 band) or Figure 11.5 (H5, H7 bands). The voltage should be:
point 2 on R350: < 5V DC

254

If the voltage measured in Step 5 is correct, go to Step 7. If it is not,
replace Q308 — see Figure 11.4 (B1 band) or Figure 11.5 (H5,
H7 bands) — and conclude with Step 8.

Remove the heat-transfer block from the main board. Replace Q311
(situated on the bottom-side of the main board next to the power
connector). Replace the heat-transfer block, and conclude with
Step 8.

Repeat Task 1 to confirm the removal of the fault, and go to “Final
Tasks” on page 147. If the repair failed or the fault could not be
found, replace the main-board assembly and go to “Final Tasks” on
page 147.

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Task 3 —
9V Power Supply

If the supply from the power connector is correct, check the 9V DC supply.
1.

Enter the CCTM command 326 1 to set the transmitter power level
very low.

Enter the CCTM command 33 to place the radio in transmit mode.

Measure the supply voltage between the 9V0 TX test point and the
GND test point (see Figure 11.6).
supply 9V0 TX: 9.0 ± 0.5V DC

Enter the CCTM command 32 to place the radio in receive mode.

If the supply measured in Step 3 is correct, go to Task 4 in
“Transmitter RF Power” on page 259. If it is not, the 9V regulator
IC601 and the associated switching circuitry Q603 are suspect; go to
Task 3 of “Power Supply Fault Finding” on page 158.

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256

Transmitter Fault Finding (50W/40W Radios)

B1 BAND

FWD PWR
TEST POINT

REV PWR
TEST POINT

9V0 TX
TEST POINT

TX INH
TEST POINT

DIRC TOP CAN

IF TOP CAN

H5, H7 BANDS

GND
TEST POINT

FWD PWR
TEST POINT

REV PWR
TEST POINT

9V0 TX
TEST POINT

TX INH
TEST POINT

D TX INH
TEST POINT

DIRC TOP CAN

IF TOP CAN

VCO
TOP
CAN

Figure 11.6
Test points for checking the 9V supply, the forward and reverse RF power, and the
inhibiting of the transmitter

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11.2

Transmitter RF Power

Introduction

If there is no fault with the power supplies, check the transmitter RF power
and correct any fault. The procedure is covered in the following eight tasks:
■

Task 4: check forward and reverse powers

■

Task 5: check RF output power

■

Task 6: power unchanged regardless of setting

■

Task 7: check for inhibiting of transmitter

■

Task 8: check temperature sensor

■

Task 9: power and current are skewed

■

Task 10: repair output matching circuitry

■

Task 11: power and current are low

The measurement points for diagnosing faults concerning the transmitter
RF power are summarized in Figure 11.7. Data required for the first task
(checking the forward and reverse powers) are supplied in Table 11.3.
Table 11.3

Voltages in millivolts corresponding to nominal forward and reverse powers

Frequency band

Forward power (318 command)

Reverse power (319 command)

2600 to 3400

< 500

3200 to 3900

< 700

3300 to 4000

< 900

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258

Transmitter Fault Finding (50W/40W Radios)

LEAD TO
TEST SET

RF CONNECTOR

LPF

DIGITAL

CLOCK

ANALOG

SIGNAL TYPES

REV PWR
TEST POINT

RECEIVER

PIN SWITCH

BUFFER
AMPLIFIER

FWD PWR
TEST POINT

DIRECTIONAL
COUPLER

50 Ω TEST LEAD
TO TEST SET

DIGITAL
BOARD

POWER
CONTROL

SYN LOCK

DIG SYN EN

DIG TX INH

D TX INH
TEST POINT

PAs
DRIVER

AND

SHAPING
FILTER

SHAPER
AND
LEVEL
SHIFTER

BIAS
LIMITER

EXCITER

OR GATE

TX REV PWR

TX FWD PWR

PWR CTL

CDC TX

FIN BIAS2

CDC TX

FIN BIAS1

CDC TX

DRV BIAS

CDC TX

SYN TX LO

TX INH
TEST POINT

CODEC
AND AUDIO
CIRCUITRY

FREQUENCY
SYNTHESIZER

Figure 11.7
Measurement and test points for diagnosing faults concerning the transmitter
RF power

TM9100 Service Manual
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Task 4 —
Check Forward and
Reverse Powers

First check the forward and reverse powers for an indication of which part
of the circuitry is suspect.
1.

Enter the CCTM command 326 4 to set the transmitter power level
high.

Enter the CCTM command 33 to place the radio in transmit mode.

Enter the CCTM command 318 to check the forward power.
The value returned is the voltage in millivolts corresponding to the
power level, and should be as shown in Table 11.3.

Confirm the above result by checking the level at the FWD PWR test
point (see Figure 11.6) using an oscilloscope.

Enter the CCTM command 319 to check the reverse power.
The value returned is the voltage in millivolts corresponding to the
power level, and should be as shown in Table 11.3.

Confirm the above result by checking the level at the REV PWR test
point (see Figure 11.6) using an oscilloscope.
If the oscilloscope momentarily indicates a very high reverse power,
then the most likely scenario is that the antenna VSWR threshold has
been exceeded and the PA has shut down to very low power.

Enter the CCTM command 32 to place the radio in receive mode.

If the values obtained in Step 3 and Step 5 are both correct, and there
is no indication of a momentary high reverse power, go to Task 5.
If one or both are incorrect, go to Step 9.

Check the connection from the RF connector on the radio to the test
set.

10.

If there is no fault, go to Step 11. If there is, rectify the fault and
repeat the above measurements.

11.

If the reverse power is momentarily too high, the directional coupler,
PIN switch or LPF is suspect; go to Task 31. Otherwise go to Task 5.

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Task 5 —
Check RF Output
Power

If the power supplies are correct, check the RF output power of the
transmitter.
1.

Enter the CCTM command 326 5 to set the transmitter power level
to the maximum value.

If not already done, program the radio with the highest frequency in
the radio’s frequency band: Enter the CCTM command 101 x x 0,
where x is the frequency in hertz. The required values for the
different frequency bands are given in Table 11.2.

Enter the CCTM command 33 to place the radio in transmit mode.

Note the RF output power measured by the test set, and note the
current reading on the DC power supply.
RF output power: > 60W (VHF), > 52W (UHF)
current: < 15A (VHF), < 12A (UHF)

Table 11.4

Enter the CCTM command 32 to place the radio in receive mode.

Program the radio with the center frequency in the radio’s frequency
band: Enter the CCTM command 101 x x 0, where x is the frequency
in hertz. The required values for the different frequency bands are
given in Table 11.2.

Repeat Step 3 to Step 5.

Program the radio with the lowest frequency in the radio’s frequency
band: Enter the CCTM command 101 x x 0, where x is the frequency
in hertz. The required values for the different frequency bands are
given in Table 11.2.

Repeat Step 3 to Step 5.

10.

Depending on the results of the above measurements, proceed to the
task indicated in Table 11.4. Note that the power and current are
considered to be skewed if they are low at one part of the frequency
band and high elsewhere.

Tasks to be performed according to the results of the power and current measurements
of Task 5

Power

Current

Task

Correct

Task 6 — Power unchanged regardless of setting

Correct

Wrong

Task 31 — Check power at directional coupler

Skewed

Task 9 — Power and current are skewed

Low (> 0.1W)

Low (> 0.5A)

Task 11 — Power and current are low

None at RF connector (< 0.1W)

Low (> 0.5A)

Task 31 — Check power at directional coupler

None at RF connector (< 0.1W)

None (< 0.5A)

Task 7 — Check for inhibiting of transmitter

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Task 6 —
Power Unchanged
Regardless of
Setting

If all the power and current values measured in Task 5 are correct, it is likely
that the power remains unchanged regardless of the power setting.
1.

Enter the following CCTM commands in turn and measure the RF
output power in each case:
■

326 4

■

326 3

■

326 2

■

326 1

The above measurements should confirm that the power remains
unchanged at all settings. Carry out Task 12 and then Task 19.

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Task 7 —
Check for Inhibiting
of Transmitter

If the transmitter is drawing no current or the wrong current, check
whether it is being inhibited. This check is also required if a CO3 error
occurs in Task 1.
1.

If not already done, enter the CCTM command 33 to place the radio
in transmit mode.

Check the logic signal at the TX INH test point (see Figure 11.6).
The signal should be:
TX INH test point: about 0V (inactive)

If the signal is inactive as required, go to Step 4. If it is active — about
1.1V — the transmitter is being inhibited; go to Step 5.

Enter the CCTM command 32 to place the radio in receive mode,
and go to Task 12 in “Biasing of PA Driver and PAs” on page 269.

Check the logic signal at the D TX INH test point; see Figure 11.18
on page 288 (B1 band) or Figure 11.6 (H5, H7 bands). The signal
should be:
D TX INH test point: about 0V (inactive)

262

If the signal is inactive as required, go to Step 8. If it is active — about
3.2V — the temperature sensor is suspect; go to Step 7.

Enter the CCTM command 32 to place the radio in receive mode,
and go to Task 8.

The lock status is possibly no longer normal. Enter the CCTM
command 72 and check the lock status.

Enter the CCTM command 32 to place the radio in receive mode.

10.

The normal lock status is 110. If it is not, proceed to the relevant
section. If it is, go to Step 11.

11.

Check for short circuits on the DIG TX INH line from the D TX INH test
point.

12.

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Task 8 —
Check Temperature
Sensor

If the transmitter is being inhibited and the logic signal at the D TX INH test
point is active, a fault in the temperature sensor might be the cause.
1.

Enter the CCTM command 47 to check the temperature reading.

Of the two numbers returned, the first is the temperature in degrees
celsius and should be about 25°C. If it is, go to Task 12 in “Biasing of
PA Driver and PAs” on page 269. If it is not, go to Step 3.

If not already done, remove the PAF TOP can.

Check D301 and the surrounding components — see Figure 11.8
(B1 band) and Figure 11.9 (H5 and H7 bands).

If there is no fault, go to “CODEC and Audio Fault Finding” on
page 371. If a fault is found, repair it, confirm the removal of the
fault, and go to “Final Tasks” on page 147. If the repair failed, replace
the main-board assembly, and go to “Final Tasks” on page 147.

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Figure 11.8

PA circuitry under the PAF TOP can and part of the directional coupler under the DIRC TOP
can (B1 band)

Q310

Q309

D301

TEMPERATURE SENSOR

C350

C349

C348

MOUNTING POINT FOR
TEST CAPACITOR

TEST PAD

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B1 BAND

TM9100 Service Manual
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Figure 11.9

PA circuitry under the PAF TOP can and part of the directional coupler under the DIRC TOP
can (H5 and H7 bands)

Q310

Q309

D301

TEMPERATURE SENSOR

C350

C349

C348

MOUNTING POINT FOR
TEST CAPACITOR

TEST PAD

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Task 9 —
Power and Current
Are Skewed

If the RF output power and the supply current are skewed, the output
matching is suspect.
1.

Remove the DIRC TOP can.

Remove the coupling capacitors C348, C349 and C350 —
see Figure 11.8 (B1) and Figure 11.9 (H5, H7).

Solder one terminal of an 82 pF (H5, H7 bands) or 680 pF (B1) test
capacitor to the PCB at the point shown in Figure 11.8 and
Figure 11.9. Mount the capacitor vertically. Use a test capacitor of
the type GRM111, DLI C17, Murata 1210, or the equivalent.

Solder a 50 Ω test lead to the PCB. Solder the outer sheath to the test
pad shown in Figure 11.8 and Figure 11.9, and solder the central
wire to the other terminal of the test capacitor.

Connect the test lead to the test set.

Program the radio with the highest frequency in the radio’s frequency
band: Enter the CCTM command 101 x x 0, where x is the frequency
in hertz.

Enter the CCTM command 33 to place the radio in transmit mode.

Note the RF output power measured by the test set, and note the
current reading on the DC power supply.
RF output power: > 70W (VHF), > 60W (UHF)
current: < 15A (VHF), < 12A (UHF)

266

Enter the CCTM command 32 to place the radio in receive mode.

10.

Program the radio with the center frequency in the band: Enter the
CCTM command 101 x x 0, where x is the frequency in hertz.

11.

Repeat Step 7 to Step 9.

12.

Program the radio with the lowest frequency in the band: Enter the
CCTM command 101 x x 0, where x is the frequency in hertz.

13.

Repeat Step 7 to Step 9.

14.

If the power and current are still skewed, go to Task 10. If the power
and current are correct, remove the test lead and test capacitor,
resolder the coupling capacitors in position, and go to Task 33 — the
PIN switch and LPF require checking.

Transmitter Fault Finding (50W/40W Radios)

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Task 10 —
Repair Output
Matching Circuitry

If the checks in Task 9 show that the power and current are still skewed,
there is a fault in the output matching circuitry.
1.

If not already done, remove the PAF TOP can.

Check for faulty, shorted or misplaced components in the circuit
between the test capacitor and the common drain of Q309 and Q310
(see Figure 11.8 and Figure 11.9). Repair any fault.

Program the radio with the highest frequency in the radio’s frequency
band: Enter the CCTM command 101 x x 0, where x is the frequency
in hertz.

Enter the CCTM command 33 to place the radio in transmit mode.

Note the RF output power measured by the test set, and note the
current reading on the DC power supply.
RF output power: > 70W (VHF), > 60W (UHD)
current: < 15A (VHF), < 12A (UHF)

Enter the CCTM command 32 to place the radio in receive mode.

Program the radio with the center frequency in the band: Enter the
CCTM command 101 x x 0, where x is the frequency in hertz.

Repeat Step 4 to Step 6.

Program the radio with the lowest frequency in the band: Enter the
CCTM command 101 x x 0, where x is the frequency in hertz.

10.

Repeat Step 4 to Step 6.

11.

Remove the test lead and test capacitor, and resolder the coupling
capacitors C348, C349 and C350 in position (see Figure 11.8 and
Figure 11.9).

12.

If the power and current are now correct at all three frequencies, the
fault has been rectified; go to “Final Tasks” on page 147. If they are
not, go to Task 26 in “RF Signal Path” on page 293.

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Task 11 —
Power and Current
Are Low

Table 11.5

If the RF output power and the supply current are uniformly low at all
frequencies, one of the PAs is suspect or the input to the PAs is reduced.
Check each PA in turn:
1.

For the first PA (Q310), enter the CCTM command 331 to check the
DAC value of final bias 1 (CDC TX FIN BIAS 1). Record the value x
returned.

Note the current reading on the DC power supply.

Enter the CCTM command 331 1 to turn off final bias 1.

Enter the CCTM command 33 to place the radio in transmit mode.

Note the RF output power measured at the test set. This should be
as shown in Table 11.5.

If the RF power is correct, go to Step 7 to repeat the check with the
second PA. If it is not, enter the CCTM command 32 to place the
radio in receive mode, and carry out Task 12 and then Task 13.

For the second PA (Q309), enter the CCTM command 332 to check
the DAC value of final bias 2 (CDC TX FIN BIAS 2). Record the value y
returned.

Note the current reading on the DC power supply.

Enter the CCTM command 332 1 to turn off final bias 2.

10.

With the radio still in transmit mode, note the RF output power
measured at the test set. This should be as shown in Table 11.5.

11.

Enter the CCTM command 32 to place the radio in receive mode.

12.

If the RF power measured in Step 10 is correct, go to “RF Signal
Path” on page 292. If it is not, carry out Task 12 and then Task 16.

RF output power of individual RF power amplifiers at different frequencies
Frequency within band

Frequency band
Lowest frequency

Center frequency

Highest frequency

38 ± 5W

48 ± 5W

33 ± 5W

16 ± 5W

17 ± 5W

21 ± 5W

25 ± 5W

32 ± 5W

40 ± 5W

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11.3

Biasing of PA Driver and PAs

Introduction

The measurements of the transmitter RF output power in “Transmitter RF
Power” might indicate a need to check the biasing of the two PAs and the
PA driver. The procedure is covered in this section. There are thirteen tasks
grouped as follows:
■

Task 12: prepare to check biasing

■

Task 13 to Task 15: check biasing of first PA

■

Task 16 to Task 18: check biasing of second PA

■

Task 19 and Task 20: check biasing of PA driver

■

Task 21 to Task 24: repair circuitry

The test and measurement points for diagnosing faults in the biasing of the
PAs and PA driver are summarized in Figure 11.10.
Task 12 —
Prepare to
Check Biasing

If the transmitter is not being inhibited, check the biasing of the two PAs
and the PA driver. First make the following preparations:
1.

Set the current limit on the DC power supply to 3A.

Enter the CCTM command 331 to check the DAC value of final bias
1 (CDC TX FIN BIAS 1) at maximum power. Record the value x returned.

Enter the CCTM command 332 to check the DAC value of final bias
2 (CDC TX FIN BIAS 2) at maximum power. Record the value y returned.

Enter the CCTM command 304 to check the DAC value of the
clamp current at the driver gate. Record the value z returned.

Enter the CCTM command 33 to place the radio in transmit mode.

Switch off all biases by entering the following CCTM commands in
sequence:
■

331 1

■

332 1

■

304 1

■

114 1023

■

334 0

■

335 0

Note the current reading on the DC power supply. This will be less
than 500mA.

With the radio still in transmit mode, check the biasing of the PAs and
PA driver, beginning with Task 13.

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270

Transmitter Fault Finding (50W/40W Radios)

PIN 3 OF
IC303

ANALOG

SIGNAL TYPES

PIN
SWITCH
AND LPF

REV PWR

BUFFER
AMPLIFIER

FWD PWR

BUFFER
AMPLIFIER

PIN 5 OF
IC303

DIRECTIONAL
COUPLER

R396

R347

PIN 9 OF
IC303

PIN 10 OF
IC303

POWER
CONTROL

R336

PIN 8 OF
IC303

GATES OF
Q309, Q310

PAs

SHAPING
FILTER

SHAPER
AND
LEVEL
SHIFTER
PIN 8 OF
IC301

PIN 1 OF
IC301

SHAPER
AND
LEVEL
SHIFTER

BIAS
LIMITER

EXCITER

PIN 14 OF
IC301

SET PWR
TEST POINT

DRIVER

GATE OF
Q306

TX REV PWR

TX FWD PWR

CDC TX PWR CTL

PWR
TEST POINT

CDC TX FIN BIAS2

FIN2
TEST POINT

CDC TX FIN BIAS1

FIN1
TEST POINT

CDC TX DRV BIAS

DRV
TEST POINT

CODEC
AND AUDIO
CIRCUITRY

FREQUENCY
SYNTHESIZER

Figure 11.10 Measurement and test points for diagnosing faults in the biasing of the PAs and PA
driver

TM9100 Service Manual
© Tait Electronics Limited August 2005

Task 13 —
Check Biasing
of First PA

Check the biasing of the first PA (Q310).
Important

Ensure that the current limit on the DC supply is 3A.
And, when entering the CCTM command 331 x, do not
specify a value x higher than that recorded in Task 12. Failure to do so might result in the destruction of the PAs.

Use a multimeter to measure the voltage at pin 14 of IC301
(see Figure 11.11 and Figure 11.12). The voltage should be:
pin 14 of IC301: < 100mV (initially)

Note the current reading on the DC power supply. As mentioned in
Step 7 of Task 12, this will be less than 500mA.

Enter the CCTM command 331 x (where x was recorded in Task 12).

Check that the voltage changes to:
pin 14 of IC301: 2 to 5V (after entry of CCTM 331 x)

Table 11.6

Also note the current reading. This should increase by an amount
approximately equal to the offset given in Table 11.6.

If the voltage and current are both correct, go to Step 7. If the voltage
is correct but not the current, go to Task 14. If neither the current
nor the voltage is correct, go to Task 15.

Enter the CCTM command 331 1 to switch off final bias 1, and go to
Task 16.

Gate biases for the PAs and PA driver at high power
Offset currents in mA

Frequency band
First PA

Second PA

PA driver

1690

150

1800

400

1800

600

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Figure 11.11 Test points and components of the shaping filter (B1 band)

DIRC TOP CAN

IC301

R334

DRV TEST POINT

SET PWR TEST POINT

R333

REV PWR TEST POINT

R340

C322

C324

IC303

R342

R347

R336

FIN2 TEST POINT

FIN1 TEST POINT

FWD PWR TEST POINT

B1 BAND

272

PWR TEST POINT

Transmitter Fault Finding (50W/40W Radios)

IF TOP CAN

TM9100 Service Manual
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Figure 11.12 Test points and components of the shaping filter (H5 and H7 bands)

DIRC TOP CAN

VCO TOP CAN

IC301

R334

SET PWR TEST POINT

R333

C322

C324

R342

IC303

R347

R336
FIN1 TEST POINT

FIN2 TEST POINT
REV PWR TEST POINT

DRV TEST POINT

FWD PWR TEST POINT

H5, H7 BANDS

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PWR TEST POINT

IF TOP CAN

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273

Task 14 —
Shaper and
Level Shifter

If the voltage measured in Task 13 is correct but not the current, either the
first PA or the shaper and level shifter for the PA is suspect.
Important

If the PAF TOP can has already been removed, go to Step 5 If it has not,
go to Step 2.

Enter the CCTM command 32 to place the radio in receive mode.

Remove the PAF TOP can.

Enter the CCTM command 33 to place the radio in transmit mode.

Enter the CCTM command 331 x (where x was recorded in Task 12).

Check that the voltage at the gate of Q310 is (see Figure 11.13 and
Figure 11.14):
gate of Q310: 2 to 5V

274

Enter the CCTM command 32 to place the radio in receive mode.

If the voltage measured above is correct, Q310 is faulty; replace the
main-board assembly and go to “Final Tasks” on page 147. If it is not
correct, go to Step 9.

Check the circuitry between pin 14 of IC301 and the gate of Q310
(see Figure 11.13 and Figure 11.14). If a fault is found, repair it,
confirm the removal of the fault, and go to “Final Tasks” on
page 147. If the repair failed or Q310 itself is faulty, replace the mainboard assembly and go to “Final Tasks” on page 147.

Transmitter Fault Finding (50W/40W Radios)

TM9100 Service Manual
© Tait Electronics Limited August 2005

Figure 11.13 PA circuitry under the PAF TOP can (B1 band)

Q310

Q309

CIRCUITRY BETWEEN
IC301 AND PAs

B1 BAND
VIA TO PIN 14 OF IC301

VIA TO PIN 8 OF IC301

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VIA TO GATE OF Q309

VIA TO GATE OF Q310

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Figure 11.14 PA circuitry under the PAF TOP can (H5 and H7 bands)

Q310

Q309
CIRCUITRY BETWEEN
IC301 AND PAs

H5, H7 BANDS

VIA TO PIN 14 OF IC301

VIA TO PIN 8 OF IC301

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Transmitter Fault Finding (50W/40W Radios)

VIA TO GATE OF Q309

VIA TO GATE OF Q310

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Task 15 —
Shaping Filter for
Power Control

If neither the voltage nor the current measured in Task 13 is correct, then
the shaping filter for the power-control circuitry or the CODEC and audio
circuitry is suspect.
Important

Ensure that the current limit on the DC supply is 3A.
And, when entering the CCTM command 331 x, do not
specify a value x higher than that recorded in Task 12.
Failure to do so might result in the destruction of the PAs.

Use the multimeter to measure the voltage at the FIN1 test point
(see Figure 11.11 and Figure 11.12). The voltage should be:
FIN1 test point: 18 ± 2mV (initially)

Enter the CCTM command 331 x (where x was recorded in Task 12).

Check that the voltage changes to:
FIN1 test point: 1.1 to 2.7V (after entry of CCTM 331 x)

Enter the CCTM command 32 to place the radio in receive mode.

If the voltage measured above is correct, go to Step 6. If it is not, go
to “CODEC and Audio Fault Finding” on page 371.

Check IC301 and the surrounding shaping-filter circuitry
(see Figure 11.11 and Figure 11.12). If a fault is found, repair it,
confirm the removal of the fault, and go to “Final Tasks” on
page 147. If the repair failed, replace the main-board assembly and go
to “Final Tasks” on page 147.

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Task 16 —
Check Biasing
of Second PA

If the biasing of the first PA is correct, check that of the second PA (Q309).
Important

Ensure that the current limit on the DC supply is 3A.
And, when entering the CCTM command 332 y, do not
specify a value y higher than that recorded in Task 12.
Failure to do so might result in the destruction of the PAs.

Use the multimeter to measure the voltage at pin 8 of IC301
(see Figure 11.11 and Figure 11.12). The voltage should be:
pin 8 of IC301: < 100mV (initially)

Note the current reading on the DC power supply. As mentioned in
Step 7 of Task 12, the current will be less than 500mA.

Enter the CCTM command 332 y (where y was recorded in Task 12).

Check that the voltage changes to:
pin 8 of IC301: 2 to 5V (after entry of CCTM 332 y)

278

Also note the current reading. This should increase by an amount
approximately equal to the offset given in Table 11.6.

If the voltage and current are both correct, go to Step 7. If the voltage
is correct but not the current, go to Task 17. If neither the current
nor the voltage is correct, go to Task 18.

Enter the CCTM command 332 1 to switch off final bias 2, and go to
Task 19.

Transmitter Fault Finding (50W/40W Radios)

TM9100 Service Manual
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Task 17 —
Shaper and
Level Shifter

If the voltage measured in Task 16 is correct but not the current, either the
second PA or the shaper and level shifter for the PA is suspect.
Important

If the PAF TOP can has already been removed, go to Step 5. If it has
not, go to Step 2.

Enter the CCTM command 32 to place the radio in receive mode.

Remove the PAF TOP can.

Enter the CCTM command 33 to place the radio in transmit mode.

Enter the CCTM command 332 y (where y was recorded in Task 12).

Check that the voltage at the gate of Q309 is (see Figure 11.13 and
Figure 11.14):
gate of Q309: 2 to 5V

Enter the CCTM command 32 to place the radio in receive mode.

If the voltage is correct, Q309 is faulty; replace the main-board
assembly and go to “Final Tasks” on page 147. If it is not, go to
Step 9.

Check the circuitry between pin 8 of IC301 and the gate of Q309
(see Figure 11.13 and Figure 11.14). If a fault is found, repair it,
confirm the removal of the fault, and go to “Final Tasks” on
page 147. If the repair failed or Q309 itself is faulty, replace the mainboard assembly and go to “Final Tasks” on page 147.

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Task 18 —
Shaping Filter for
Power Control

If neither the voltage nor the current measured in Task 16 is correct, then
the shaping filter for the power-control circuitry or the CODEC and audio
circuitry is suspect.
Important

Use the multimeter to measure the voltage at the FIN2 test point
(see Figure 11.11 and Figure 11.12). The voltage should be:
FIN2 test point: 18 ± 2V (initially)

Enter the CCTM command 332 y (where y was recorded in Task 12).

Check that the voltage changes to:
FIN2 test point: 1.1 to 2.7V (after entry of CCTM 332 y)

280

Enter the CCTM command 32 to place the radio in receive mode.

If the voltage measured above is correct, go to Step 6. If it is not, go
to “CODEC and Audio Fault Finding” on page 371.

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Task 19 —
Biasing of PA Driver
—
DRV test point

If there is no fault in the biasing of the PAs, investigate the biasing of the PA
driver (Q306). First check the DRV test point.
Important

Ensure that the current limit on the DC supply is 3A.
And, when entering the CCTM command 304 z, do not
specify a value z higher than that recorded in Task 12.
Failure to do so might result in the destruction of the PA
driver.

Note the current reading on the DC power supply. As mentioned in
Step 7 of Task 12, the current will be less than 500mA.

Enter the CCTM command 304 z (where z was recorded in Task 12)
to switch on the clamp current.

Note the current reading on the DC power supply.

Compare the above current readings. The current should increase by
an amount approximately equal to the offset given in Table 11.6.
If it does, go to Task 21. If it does not, go to Step 5.

Check as follows that the voltage from the DAC is changing:
First enter the CCTM command 304 1 to switch off the bias.

Measure the voltage at the DRV test point (CDC TX DRV BIAS)
(see Figure 11.11 and Figure 11.12). The voltage should be:
DRV test point: < 0.1V (after entry of CCTM 304 1)

Enter the CCTM command 304 z (where z was recorded in Task 12)
to change the DAC value of the clamp current.

The voltage should increase to:
DRV test point: 0.8 to 2.5V (after entry of CCTM 304 z)

If the voltage does change, go to Task 20. If it does not, go to
Step 10.

10.

Enter the CCTM command 32 to place the radio in receive mode,
and go to “CODEC and Audio Fault Finding” on page 371.

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Task 20 —
Biasing of
PA Driver—
SET PWR test point

If the voltage at the DRV test point is correct, check that at the SET PWR test
point.
1.

Check the voltage at the SET PWR test point (see Figure 11.11 and
Figure 11.12):
SET PWR test point: 2 to 5V

If the voltage is correct, go to Step 3. If it is not, go to Task 21.

If the PAD TOP can has already been removed, go to Step 7. If it has
not, go to Step 4.

Enter the CCTM command 32 to place the radio in receive mode.

Remove the PAD TOP can.

Enter the CCTM command 33 to place the radio in transmit mode.

Check the voltage on the gate of Q306 (see Figure 11.15 and
Figure 11.16):
gate of Q306: 2 to 5V

282

Enter the CCTM command 32 to place the radio in receive mode.

If the voltage is correct, replace Q306; confirm the removal of the
fault and go to “Final Tasks” on page 147. If it is not, go to Task 23.

Transmitter Fault Finding (50W/40W Radios)

TM9100 Service Manual
© Tait Electronics Limited August 2005

Figure 11.15 PA driver circuitry under the PAD TOP can (B1 band)

PAD TOP
COMPONENTS C310,
R324 AND R327

R327
C310
R324

Q306

Q3504

GATE OF Q306

B1 BAND

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Figure 11.16 PA driver circuitry under the PAD TOP can (H5 and H7 bands)

COMPONENTS C310,
R324 AND R327

PAD TOP

R324
C310

Q306

GATE OF Q306

H5, H7 BANDS

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Task 21 —
Check Power
Control

Check the power-control circuitry if the clamp current for the PA driver is
correct or if the voltage at the SET PWR test point is incorrect.
Important

Ensure that the current limit on the DC supply is 3A.
And, when entering the CCTM command 304 z, do not
specify a value z higher than that recorded in Task 12. Failure to do so might result in the destruction of the PA driver.

Enter the CCTM command 304 z (where z was recorded in Task 12).

Note the current reading on the DC power supply.

Enter the CCTM command 114 0 to switch off the power.

Note the current reading on the DC power supply.

Compare the above current readings. The current should decrease by
an amount approximately equal to the offset given in Table 11.6.
If it does, go to Task 26 in “RF Signal Path” on page 293. If it does
not, go to Step 6.

Check that the voltage from the DAC is changing. Measure the
voltage at the PWR test point (CDC TX PWR CTL) (see Figure 11.11 and
Figure 11.12).

Enter the CCTM command 114 1023. The voltage should increase
to:
PWR test point: 2.4 ± 0.1V

Enter the CCTM command 32 to place the radio in receive mode.

If the voltage at the PWR test point increases as required, go to
Task 22. If it does not, go to “CODEC and Audio Fault Finding” on
page 371.

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Figure 11.17 Circuitry under the DIRC TOP can

R3035

B1 BAND

286

D305

R383

H5, H7 BANDS

Transmitter Fault Finding (50W/40W Radios)

TM9100 Service Manual
© Tait Electronics Limited August 2005

Task 22 —
Directional Coupler
and Buffer
Amplifiers

Table 11.7

Following the checks in Task 19 to Task 21, locate the fault and repair the
circuitry as described in the remaining tasks of the section. In this task any
faults in the directional coupler or the buffer amplifiers will be located.
1.

Cycle the power.

Enter the CCTM command 326 5 to set the transmitter to maximum
power. Enter the CCTM command 33 to place the radio in transmit
mode.

Measure the voltage at pin 9 of IC303 in the power-control circuit
(see Figure 11.11 and Figure 11.12).

The above voltage should be as given in Table 11.7. If it is, go to
Task 24. If it is not, go to Step 5.

Check the voltage at the FWD PWR test point (pin 5 of IC303) and at
the REV PWR test point (pin 3 of IC303) (see Figure 11.11 and
Figure 11.12). Note that the probe impedance might affect these
measurements.

Enter the CCTM command 32 to place the radio in receive mode.

The voltages measured in Step 5 should be as given in Table 11.7.
If they are, go to Step 10. If the FWD PWR voltage is incorrect, go to
Step 8. If the REV PWR voltage is incorrect, go to Step 9.

Voltages at IC303 at maximum power (70 W for B1 band, and 60W for H5 and H7)
Voltage (V)

Frequency band

Frequency (MHz)
Pin 3 (REV PWR)

Pin 9

Pin 5 (FWD PWR)

136
155
174

2.6 ± 0.5
2.9 ± 0.5
3.2 ± 0.5

0.4 ± 0.3
0.4 ± 0.3
0.5 ± 0.3

3.1 ± 0.5
3.4 ± 0.5
3.9 ± 0.5

400
435
470

2.8 ± 0.5
3.0 ± 0.5
3.3 ± 0.5

0.6 ± 0.4
0.6 ± 0.4
0.5 ± 0.4

3.3 ± 0.5
3.7 ± 0.5
3.9 ± 0.5

450
485
520

3.9 ± 0.5
4.1 ± 0.5
4.4 ± 0.5

0.6 ± 0.4
0.8 ± 0.4
0.8 ± 0.4

4.4 ± 0.5
4.6 ± 0.5
5.0 ± 0.5

Remove the DIRC TOP can. Check the components of the directional
coupler (see Figure 11.17) and go to Step 11.

Remove the DIRC TOP can. Check D305 and R3035 (B1) or R383
(H5, H7) (see Figure 11.17). If there is no fault, the PIN switch or
LPF or both are suspect; go to Task 33. If there is a fault, go to
Step 11.

10.

In the buffer amplifiers, check R340 and R341 (see Figure 11.11,
Figure 11.18 and Figure 11.19).

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Task 23 —
Power Control
for PA Driver

11.

Repair any fault revealed by the above checks. Replace IC303 if none
of the other components is faulty (see Figure 11.11 and
Figure 11.12).

12.

Confirm the removal of the fault and go to “Final Tasks” on
page 147. If the repair failed, replace the main-board assembly and go
to “Final Tasks” on page 147.

In this task any faults in the path between the power-control circuit and the
PA driver will be located, as well as any fault with the PA driver.
1.

Check for short circuits at the gate of the PA driver Q306. Check
R333, R336 (see Figure 11.11 and Figure 11.12), C310, R324
and R327 (see Figure 11.15 and Figure 11.16) between the
power-control circuit and Q306.

Repair any fault revealed by the checks in Step 1. If none of the
above-mentioned components is faulty, replace Q306
(see Figure 11.15 and Figure 11.16).

Confirm the removal of the fault and go to “Final Tasks” on
page 147. If the repair failed, replace the main-board assembly and go
to “Final Tasks” on page 147.

Figure 11.18 Components of concern on the bottom-side of the main board (B1 band)

COPPER PLATE

VCO BOT CAN

D311

B1 BAND

288

NB BOT CAN

Transmitter Fault Finding (50W/40W Radios)

R341

C319

R396

D TX INH TEST POINT

TM9100 Service Manual
© Tait Electronics Limited August 2005

Figure 11.19 Components of concern on the bottom-side of the main board (H5 and H7 bands)

COPPER PLATE

C319

VCO BOT CAN

R396

R341

R340

H5, H7 BANDS

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Task 24 —
Power Control

In this task any faults in the power-control circuitry will be located:
1.

Measure the voltage at pin 8 of IC303 (see Figure 11.11 and
Figure 11.12) in the power-control circuit. The voltage should be:
pin 8 of IC303: 7.4 ± 0.5V

If the voltage is correct, go to Step 3. If it is not, enter the CCTM
command 32 and return to Task 23.

Measure the voltage at pin 10 of IC303 in the power-control circuit.
The voltage should be:
pin 10 of IC303: 4.8 ± 0.5V

290

If the voltage is correct, go to Step 5. If it is not, go to Task 25.

Enter the CCTM command 32 to place the radio in receive mode.

Check C322, C324, R342, R347 (see Figure 11.11 and
Figure 11.12) and R396 (see Figure 11.18 and Figure 11.19) in
the power-control circuit. Repair any fault. Replace IC303 if none
of the other components is faulty.

Confirm the removal of the fault and go to “Final Tasks” on
page 147. If the repair failed, replace the main-board assembly and go
to “Final Tasks” on page 147.

Transmitter Fault Finding (50W/40W Radios)

TM9100 Service Manual
© Tait Electronics Limited August 2005

Task 25 —
Shaping Filter

In this task any faults in the shaping-filter circuitry will be located.
1.

With the radio still in transmit mode, measure the voltage at pin 1 of
IC301 (see Figure 11.11 and Figure 11.12) in the shaping-filter
circuit. The voltage should be:
pin 1 of IC301: 4.8 ± 0.5V

Enter the CCTM command 32 to place the radio in receive mode.

If the voltage measured in Step 1 is correct, go to Step 4. If it is not,
go to Step 5.

Check the components R334 (see Figure 11.11 and Figure 11.12)
and C319 (see Figure 11.18 and Figure 11.19) and go to Step 6.

Check the components between the PWR test point and pin 1 of
IC301 (see Figure 11.11 and Figure 11.12) and go to Step 6.

Repair any fault revealed by the checks in Step 4 and Step 5. Replace
IC301 if none of the other components is faulty.

Confirm the removal of the fault and go to “Final Tasks” on
page 147. If the repair failed, replace the main-board assembly and go
to “Final Tasks” on page 147.

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11.4

RF Signal Path
The RF signal path extends from the output of the frequency synthesizer to
the LPF. This section of circuitry will require investigation either following
certain checks in “Transmitter RF Power” or if the biasing checks of
“Biasing of PA Driver and PAs” reveal no fault. The procedure is divided
into ten tasks grouped as follows:

Introduction

■

Task 26 to Task 30: initial RF signal path

■

Task 31 and Task 32: directional coupler

■

Task 33 and Task 34: PIN switch

■

Task 35: LPF

The initial signal path includes the exciter and PA driver. The directional
coupler, PIN switch, and LPF make up the final signal path.
The measurement points for diagnosing faults in the signal path are
summarized in Figure 11.20.
Figure 11.20 Measurement points for diagnosing faults in the RF signal path
SIGNAL TYPES

STAGE 3
EXCITER
OUTPUT

SYNTHESIZER
OUTPUT
SYN TX LO

ANALOG

DRIVER

PAs

EXCITER
C307

L314

C3500

TEST
CAPACITOR
GATES OF
Q309, Q310

50 Ω TEST
LEAD TO
TEST SET

PA DRIVER
OUTPUT AT
DRAIN OF Q306

STAGE 2
OUTPUT
AT C3509

STAGE 1
OUTPUT
AT C3505

FREQUENCY
SYNTHESIZER

DIRECTIONAL
COUPLER

RECEIVER
PIN
SWITCH
TEST
CAPACITOR
50 Ω TEST
LEAD TO
TEST SET

RF CONNECTOR

292

LPF

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Task 26 —
Output of
Frequency
Synthesizer

The first point to check in the initial RF signal path is the output SYN TX LO
from the frequency synthesizer. This signal is input to the exciter at C300.
1.

For test purposes select a representative power level and frequency
from Table 11.8 (B1 band), Table 11.9 (H5) or Table 11.10 (H7).
(Note that the data for these tables were obtained using an
RFP5401A RF probe.)

To set the power level, enter the CCTM command 326 x, where x
defines the level. To set the frequency, enter the CCTM command
101 x x 0, where x is the frequency in hertz.

Enter the CCTM command 33 to place the radio in transmit mode.

Use an RFP5401A RF probe or the equivalent to measure the RF
voltage after C3500 (see Figure 11.21 and Figure 11.22). Earth the
probe to the FCL TOP can adjacent to the PA driver circuitry.
The required voltage should be as given in Table 11.8 (B1 band),
Table 11.9 (H5) or Table 11.10 (H7).

Enter the CCTM command 32 to place the radio in receive mode.

If the voltage measured above is correct, go to Task 27. If it is not, go
to Step 7.

Check C3500 (see Figure 11.21 and Figure 11.22). If C3500 is not
faulty, go to “Frequency Synthesizer Fault Finding” on page 169.
If C3500 is faulty, replace it and return to Step 2.

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Figure 11.21 PA driver circuitry under the PAD TOP can (B1 band)
OUTPUT OF PA DRIVER

PAD TOP

OUTPUT OF STAGE 3
OF EXCITER AT C307

JUNCTION OF
R3525 AND C3512

Q306

C307

Q3504

OUTPUT OF STAGE 2
OF EXCITER AT C3509
Q3505

Q3502

C3505

C3500

Q3501

R3525
C3509

FCL TOP CAN

B1 BAND

OUTPUT OF STAGE 1 OF
EXCITER AT C3505
SYNTHESIZER
OUTPUT AT C3500

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Figure 11.22 PA driver circuitry under the PAD TOP can (H5 and H7 bands)
OUTPUT OF PA DRIVER

PAD TOP

OUTPUT OF STAGE 3
OF EXCITER AT C307

C317

Q306

C389

JUNCTION OF
R3525 AND C3512

Q3504

C307

Q3505

OUTPUT OF STAGE 2
OF EXCITER AT C3509

C3509

Q3502

C3505

C3500

Q3501

R3525

FCL TOP CAN

H5, H7 BANDS

OUTPUT OF STAGE 2 OF
EXCITER AT C3505
SYNTHESIZER
OUTPUT AT C3500

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Table 11.8

RF voltages along the initial RF signal path of the VHF radio (B1 band)
RF voltages (V)

Power
level (W)

Frequency
(MHz)

Synthesizer
output

Exciter
stage 1

Exciter
stage 2

Exciter
stage 3

Driver
output

136
155
174

0.3 ± 0.1
0.3 ± 0.1
0.2 ± 0.1

0.6 ± 0.2
0.6 ± 0.2
0.7 ± 0.2

2.7 ± 0.5
2.2 ± 0.5
1.7 ± 0.5

4.0 ± 0.5
3.7 ± 0.5
4.0 ± 0.5

9.9 ± 0.5
8.4 ± 0.5
8.4 ± 0.5

136
155
174

0.3 ± 0.1
0.2 ± 0.1
0.2 ± 0.1

0.6 ± 0.2
0.6 ± 0.2
0.7 ± 0.2

2.7 ± 0.5
2.2 ± 0.5
1.7 ± 0.5

4.0 ± 0.5
3.7 ± 0.5
4.0 ± 0.5

11.8 ± 0.5
10.0 ± 0.5
10.0 ± 0.5

136
155
174

0.3 ± 0.1
0.2 ± 0.1
0.2 ± 0.1

0.6 ± 0.2
0.6 ± 0.2
0.7 ± 0.2

2.7 ± 0.5
2.2 ± 0.5
1.7 ± 0.5

4.0 ± 0.5
3.7 ± 0.5
4.0 ± 0.5

14.3 ± 0.5
13.5 ± 0.5
14.7 ± 0.5

136
155
174

0.3 ± 0.1
0.2 ± 0.1
0.2 ± 0.1

0.6 ± 0.2
0.6 ± 0.2
0.7 ± 0.2

2.7 ± 0.5
2.2 ± 0.5
1.7 ± 0.5

4.0 ± 0.5
3.7 ± 0.5
4.0 ± 0.5

15.6 ± 0.5
15.0 ± 0.5
15.6 ± 0.5

136
155
174

0.3 ± 0.1
0.2 ± 0.1
0.3 ± 0.1

0.6 ± 0.2
0.6 ± 0.2
0.7 ± 0.2

2.7 ± 0.5
2.2 ± 0.5
1.7 ± 0.5

4.0 ± 0.5
3.7 ± 0.5
4.0 ± 0.5

24.5 ± 0.5
29.0 ± 0.5
22.0 ± 0.5

Table 11.9

RF voltages along the initial RF signal path of the UHF radio (H5 band)
RF voltages (V)

Power
level (W)

Frequency
(MHz)

Synthesizer
output

Exciter
stage 1

Exciter
stage 2

Exciter
stage 3

Driver
output

400
435
470

0.3 ± 0.1
0.4 ± 0.1
0.3 ± 0.1

1.2 ± 0.2
2.4 ± 0.2
1.1 ± 0.2

4.2 ± 0.5
2.7 ± 0.5
2.1 ± 0.5

9.2 ± 0.5
6.8 ± 0.5
4.8 ± 0.5

3.0 ± 0.5
2.9 ± 0.5
2.0 ± 0.5

400
435
470

0.3 ± 0.1
0.3 ± 0.1
0.3 ± 0.1

1.2 ± 0.2
2.4 ± 0.2
1.1 ± 0.2

4.2 ± 0.5
2.7 ± 0.5
2.1 ± 0.5

9.2 ± 0.5
6.8 ± 0.5
4.8 ± 0.5

4.1 ± 0.5
3.8 ± 0.5
2.5 ± 0.5

400
435
470

0.4 ± 0.1
0.3 ± 0.1
0.3 ± 0.1

1.2 ± 0.2
2.4 ± 0.2
1.1 ± 0.2

4.2 ± 0.5
2.7 ± 0.5
2.1 ± 0.5

9.2 ± 0.5
6.8 ± 0.5
4.8 ± 0.5

4.8 ± 0.5
4.2 ± 0.5
3.0 ± 0.5

400
435
470

0.3 ± 0.1
0.3 ± 0.1
0.3 ± 0.1

1.2 ± 0.2
2.4 ± 0.2
1.1 ± 0.2

4.2 ± 0.5
2.7 ± 0.5
2.1 ± 0.5

9.2 ± 0.5
6.8 ± 0.5
4.8 ± 0.5

4.6 ± 0.5
4.0 ± 0.5
2.9 ± 0.5

400
435
470

0.3 ± 0.1
0.3 ± 0.1
0.3 ± 0.1

1.2 ± 0.2
2.4 ± 0.2
1.1 ± 0.2

4.2 ± 0.5
2.7 ± 0.5
2.1 ± 0.5

9.2 ± 0.5
6.8 ± 0.5
4.8 ± 0.5

8.1 ± 0.5
7.3 ± 0.5
5.3 ± 0.5

296

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Table 11.10 RF voltages along the initial RF signal path of the UHF radio (H7 band)
RF voltages (V)
Power
level (W)

Frequency
(MHz)

Synthesizer
output

Exciter
stage 1

Exciter
stage 2

Exciter
stage 3

Driver
output

450
485
520

0.2 ± 0.1
0.2 ± 0.1
0.2 ± 0.1

1.1 ± 0.2
1.0 ± 0.2
1.2 ± 0.2

2.2 ± 0.5
1.9 ± 0.5
0.9 ± 0.5

5.7 ± 0.5
3.4 ± 0.5
2.4 ± 0.5

2.5 ± 0.5
2.0 ± 0.5
0.9 ± 0.5

450
485
520

0.2 ± 0.1
0.2 ± 0.1
0.2 ± 0.1

1.1 ± 0.2
1.0 ± 0.2
1.2 ± 0.2

2.2 ± 0.5
1.9 ± 0.5
0.9 ± 0.5

5.7 ± 0.5
3.4 ± 0.5
2.4 ± 0.5

3.1 ± 0.5
2.4 ± 0.5
1.1 ± 0.5

450
485
520

0.2 ± 0.1
0.2 ± 0.1
0.2 ± 0.1

1.1 ± 0.2
1.0 ± 0.2
1.2 ± 0.2

2.2 ± 0.5
1.9 ± 0.5
0.9 ± 0.5

5.7 ± 0.5
3.4 ± 0.5
2.4 ± 0.5

3.6 ± 0.5
2.9 ± 0.5
1.4 ± 0.5

450
485
520

0.2 ± 0.1
0.1 ± 0.1
0.1 ± 0.1

1.1 ± 0.2
1.0 ± 0.2
1.2 ± 0.2

2.2 ± 0.5
1.9 ± 0.5
0.9 ± 0.5

5.7 ± 0.5
3.4 ± 0.5
2.4 ± 0.5

3.8 ± 0.5
3.2 ± 0.5
1.5 ± 0.5

450
485
520

0.2 ± 0.1
0.2 ± 0.1
0.2 ± 0.1

1.1 ± 0.2
1.0 ± 0.2
1.2 ± 0.2

2.2 ± 0.5
1.9 ± 0.5
0.9 ± 0.5

5.7 ± 0.5
3.4 ± 0.5
2.4 ± 0.5

7.8 ± 0.5
4.8 ± 0.5
2.8 ± 0.5

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297

Task 27 —
Output of First
Stage of Exciter

298

If the synthesizer output is correct, check the output at C3505 of the first
stage of the exciter circuit.
1.

If not already done, remove the PAD TOP can.

Enter the CCTM command 326 x, where x defines the power level
selected in Task 26.

Enter the CCTM command 101 x x 0, where x is the frequency
selected in Task 26.

Enter the CCTM command 33 to place the radio in transmit mode.

Measure the RF voltage after C3505 (see Figure 11.21 and
Figure 11.22). (Use an RFP5401A RF probe or the equivalent.)
The required voltage should be as given in Table 11.8 (B1 band),
Table 11.9 (H5) or Table 11.10 (H7).

Enter the CCTM command 32 to place the radio in receive mode.

If the voltage measured above is correct, go to Task 29. If it is not, go
to Step 8.

Check the components around Q3501 (see Figure 11.21 and
Figure 11.22).

Repair any fault revealed by the above checks. Replace Q3501
(see Figure 11.21 and Figure 11.22) if none of the other
components is faulty.

10.

Confirm the removal of the fault and go to “Final Tasks” on
page 147. If the repair failed, replace the main-board assembly and go
to “Final Tasks” on page 147.

Transmitter Fault Finding (50W/40W Radios)

TM9100 Service Manual
© Tait Electronics Limited August 2005

Task 28 —
Output of Second
Stage of Exciter

If the output of the first stage of the exciter circuit is correct, check that of
the second stage at C3509:
1.

With the radio still in transmit mode, measure the RF voltage after
C3509 (see Figure 11.21 and Figure 11.22). (Use an RFP5401A
RF probe or the equivalent.) The required voltage should be as given
in Table 11.8 (B1 band), Table 11.9 (H5) or Table 11.10 (H7).

If the voltage is correct, go to Task 30. If it is not, go to Step 3.

Enter the CCTM command 32 to place the radio in receive mode.

Check the components around Q3502 (see Figure 11.21 and
Figure 11.22).

Repair any fault revealed by the above checks. Replace Q3502
(see Figure 11.21 and Figure 11.22) if none of the other
components is faulty.

Confirm the removal of the fault and go to “Final Tasks” on
page 147. If the repair failed, replace the main-board assembly and go
to “Final Tasks” on page 147.

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Transmitter Fault Finding (50W/40W Radios)

299

Task 29 —
Output of Third
Stage of Exciter

If the output of the second stage of the exciter circuit is correct, check that
of the third and final stage at C307.
1.

With the radio still in transmit mode, measure the RF voltage after
C307 (see Figure 11.21 and Figure 11.22). (Use an RFP5401A
RF probe or the equivalent.) The required voltage should be as given
in Table 11.8 (B1 band), Table 11.9 (H5) or Table 11.10 (H7).

If the voltage is correct, go to Task 30. If it is not, go toStep 3.

With the radio still in transmit mode, measure the RF voltage at the
junction of R3525 and C3512 (see Figure 11.21 and
Figure 11.22). The voltage should be:
junction of R3525 and C3512: 1.3 ± 0.2V (B1)
1.8 ± 0.2V (H5, H7)

300

Enter the CCTM command 32 to place the radio in receive mode.

If the voltage measured in Step 3 is correct, go to Step 7. If it is not,
go to Step 6.

Check the components around Q3504 (see Figure 11.21 and
Figure 11.22). Repair any fault. Replace Q3504 if none of the other
components is faulty. Conclude with Step 8.

Check the components around Q3505 (see Figure 11.21 and
Figure 11.22). Repair any fault. Replace Q3505 if none of the other
components is faulty.

Confirm the removal of the fault and go to “Final Tasks” on
page 147. If the repair failed, replace the main-board assembly and go
to “Final Tasks” on page 147.

Transmitter Fault Finding (50W/40W Radios)

TM9100 Service Manual
© Tait Electronics Limited August 2005

Task 30 —
Output of PA Driver

If the exciter output is correct, check the output of the PA driver at the
drain of Q306. If necessary, also check the signal at the gates of the PAs
Q309 and Q310. This is the last point in the initial RF signal path.
1.

With the radio still in transmit mode, measure the RF voltage at the
drain of Q306 (B1 — see Figure 11.21) or after C317 and C389
(H5, H7 — see Figure 11.22). (Use an RFP5401A RF probe or the
equivalent.) The required voltage should be as given in Table 11.8
(B1), Table 11.9 (H5) or Table 11.10 (H7).

Enter the CCTM command 32 to place the radio in receive mode.

If the voltage measured above is correct, go to Step 7. If it is not, go
to Step 4.

Check the components between C307 and Q306 (see Figure 11.21
and Figure 11.22).

If the above checks reveal a fault, go to Step 6. If they do not, go to
Task 12 in “Biasing of PA Driver and PAs” on page 269.

Repair the fault. Confirm the removal of the fault and go to “Final
Tasks” on page 147. If the repair failed, replace the main-board
assembly and go to “Final Tasks” on page 147.

If not already done, remove the PAF TOP can.

Enter the CCTM command 326 5 to set the power level to the
maximum, and then the command 33 to place the radio in transmit
mode.

Measure the RF voltage at the gates of the PAs Q309 and Q310
(see Figure 11.23 and Figure 11.24).

10.

Enter the CCTM command 32 to place the radio in receive mode.

11.

If an RF voltage is present, there is no fault in the initial RF signal
path; go to Task 31. If there is no RF voltage, go to Step 12.

12.

Check the components of the interstage matching circuitry between
the PA driver Q306 and the gates of the PAs Q309 and Q310
(see Figure 11.23 and Figure 11.24).

13.

If a fault is found, repair it, confirm the removal of the fault, and go
to “Final Tasks” on page 147. If the repair failed or the fault could
not be found, replace the main-board assembly and go to “Final
Tasks” on page 147.

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Transmitter Fault Finding (50W/40W Radios)

301

Figure 11.23 Components of the interstage matching circuitry between the PA driver Q306 and the
PAs Q309 and Q310 (B1 band)

Q310

Q306

Q309

B1 BAND
PAF TOP CAN

302

Transmitter Fault Finding (50W/40W Radios)

PAD TOP CAN

TM9100 Service Manual
© Tait Electronics Limited August 2005

Figure 11.24 Components of the interstage matching circuitry between the PA driver Q306 and the
PAs Q309 and Q310 (H5 and H7 bands)

Q310

Q306

Q309

H5, H7 BANDS
PAF TOP CAN

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PAD TOP CAN

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303

Task 31 —
Check Power at
Directional Coupler

If, as determined in Task 26 to Task 30, there is no fault in the initial RF
signal path, investigate the final signal path. This part of the circuitry may
also require investigation following certain checks in “Transmitter RF
Power”. Begin by checking the directional coupler as follows:
1.

If not already done, remove the DIRC TOP can.

Remove the coupling capacitors C348, C349, C350
(see Figure 11.25 and Figure 11.26).

Solder one terminal of an 82pF (H5, H7 bands) or 680pF (B1) test
capacitor to the PCB at the point shown in Figure 11.25 and
Figure 11.26. Mount the capacitor vertically. Use a test capacitor of
the type GRM111, DLI C17, Murata 1210, or the equivalent.

Solder a 50Ω test lead to the PCB: Solder the outer sheath to the test
pad shown in Figure 11.25 and Figure 11.26, and solder the central
wire to the other terminal of the test capacitor.

Connect the test lead to the test set.

Enter the CCTM command 326 5 to set the transmitter power level
to the maximum.

Enter the CCTM command 101 x x 0, where x is the lowest
frequency (in hertz) for maximum power, as given in Table 11.8
(B1 band), Table 11.9 (H5) or Table 11.10 (H7).

Enter the CCTM command 33 to place the radio in transmit mode.

Measure the RF output power. This should be:
RF output power: more than 70W (B1 band)
more than 60W (H5, H7 bands)

304

10.

Enter the CCTM command 32 to place the radio in receive mode.

11.

Enter the CCTM command 101 x x 0, where x is the highest
frequency (in hertz) for maximum power, as given in Table 11.8
(B1 band), Table 11.9 (H5) or Table 11.10 (H7).

12.

Repeat Step 8 to Step 10.

13.

If the power measured in both the above cases exceeds 70W (B1) or
60W (H5, H7), go to Step 14. If it does not, go to Task 32.

14.

Remove the test lead and test capacitor, resolder the coupling
capacitors in position, and go to Task 33.

Transmitter Fault Finding (50W/40W Radios)

TM9100 Service Manual
© Tait Electronics Limited August 2005

Figure 11.25 Circuitry under the DIRC TOP can, and the points for attaching the test lead and test
capacitor (B1 band)

MOUNTING POINT FOR TEST CAPACITOR

C350

C349

C348

TEST PAD

B1 BAND

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Figure 11.26 Circuitry under the DIRC TOP can, and the points for attaching the test lead and test
capacitor (H5 and H7 bands)

MOUNTING POINT FOR TEST CAPACITOR

C350

C349

C348

TEST PAD

H5, H7 BANDS

306

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Task 32 —
Repair Circuitry

If the RF output power measured in Task 31 is low, there is a fault in the
circuit between the common drain of the PAs and the test capacitor.
1.

If not already done, remove the PAF TOP can.

Check for faulty, shorted or misplaced components in the circuit
between the test capacitor and the common drain of Q309 and Q310
(see Figure 11.8 and Figure 11.9).

Repair any fault revealed by the above checks and go to Step 5. If no
fault could be found, go to Step 4.

Remove the test lead and test capacitor, resolder the coupling
capacitors C348, C349 and C350 in position (see Figure 11.25 and
Figure 11.26), and go to Task 26.

With the test lead still connected to the test set, enter the CCTM
command 326 5 to set the transmitter power level to the maximum.

Enter the CCTM command 101 x x 0, where x is the lowest
frequency (in hertz) for maximum power, as given in Table 11.8
(B1 band), Table 11.9 (H5) or Table 11.10 (H7).

Enter the CCTM command 33 to place the radio in transmit mode.

Measure the RF output power. This should be:
RF output power: more than 70W (B1 band)
more than 60W (H5, H7 bands)

Enter the CCTM command 32 to place the radio in receive mode.

10.

Enter the CCTM command 101 x x 0, where x is the highest
frequency (in hertz) for maximum power, as given in Table 11.8
(B1 band), Table 11.9 (H5) or Table 11.10 (H7).

11.

Repeat Step 7 to Step 9.

12.

Remove the test lead and test capacitor, and resolder the coupling
capacitors C348, C349 and C350 in position (see Figure 11.25 and
Figure 11.26).

13.

If the power in both the above cases is now correct, the fault has been
rectified; go to “Final Tasks” on page 147. If it is not, the repair
failed; replace the main-board assembly and go to “Final Tasks” on
page 147.

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Transmitter Fault Finding (50W/40W Radios)

307

Task 33 —
Check PIN Switch

In checking the final RF signal path, if no fault is found in the directional
coupler, then check the PIN switch next. The PIN switch may also require
investigation following certain checks in “Transmitter RF Power”.
1.

Remove the LPF TOP can.

Remove the three blocking capacitors C361, C362 and C363
(see Figure 11.27).

Solder one terminal of a 56 pF (B1 band) or 18 pF (H5, H7) test
capacitor to the PCB at the point shown in Figure 11.27. Mount the
capacitor vertically. Use a test capacitor of the type GRM111, DLI
C17, Murata 1210, or the equivalent.

Solder a 50 Ω test lead to the PCB. Solder the outer sheath to the test
pad shown in Figure 11.27, and solder the central wire to the other
terminal of the test capacitor.

Connect the test lead to the test set.

Enter the CCTM command 326 5 to set the transmitter power level
to the maximum.

Enter the CCTM command 101 x x 0, where x is the lowest
frequency (in hertz) for maximum power, as given in Table 11.8
(B1 band), Table 11.9 (H5) or Table 11.10 (H7).

Enter the CCTM command 33 to place the radio in transmit mode.

Measure the RF output power. This should be:
RF output power: more than 70W (B1 band)
more than 60W (H5, H7 bands)

308

10.

Enter the CCTM command 32 to place the radio in receive mode.

11.

Enter the CCTM command 101 x x 0, where x is the highest
frequency (in hertz) for maximum power, as given in Table 11.8
(B1 band), Table 11.9 (H5) or Table 11.10 (H7).

12.

Repeat Step 8 to Step 10.

13.

If the power in both the above cases exceeds 70W (B1) or 60W (H5,
H7), go to Step 14. If it does not, the circuitry of the PIN switch is
suspect; go to Task 34.

14.

Remove the test lead and test capacitor, resolder the blocking
capacitors in position, and go to Task 35.

Transmitter Fault Finding (50W/40W Radios)

TM9100 Service Manual
© Tait Electronics Limited August 2005

Figure 11.27 Circuitry under the PIN TOP can, and points for attaching the test lead and test capacitor

C363

C361

C363

C361

C362

TEST PAD

MOUNTING POINT FOR
TEST CAPACITOR
D307

D3507

B1 BAND

H5, H7 BANDS

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Transmitter Fault Finding (50W/40W Radios)

309

Task 34 —
Repair PIN switch

If the RF power at the PIN switch is low, the switch is not drawing the
expected current or the diode is faulty. Check the circuit as follows:
1.

Remove the PIN TOP can.

Perform a diode check of D307 (B1 band) or D3507 (H5, H7 bands)
(see Figure 11.27). If it is not faulty, go to Step 3. If it is, replace
D307 or D3507, and go to Step 4.

Check the +9V0_TX supply to the PIN switch via the following
resistors on the bottom-side of the PCB (see Figure 11.28 and
Figure 11.29):
■

B1 band: R389 and R390

■

H5, H7 bands: R3000, R389 and R390

If any resistor is faulty, replace the resistor as well as D307 (B1) or
D3507 (H5, H7). (A faulty resistor is likely to have resulted in damage
to D307 or D3507.)
4.

With the test lead still connected to the test set, enter the CCTM
command 326 5 to set the transmitter power level to the maximum.

Enter the CCTM command 101 x x 0, where x is the lowest
frequency (in hertz) for maximum power, as given in Table 11.8
(B1 band), Table 11.9 (H5) or Table 11.10 (H7).

Enter the CCTM command 33 to place the radio in transmit mode.
Again measure the RF output power. This should be:
RF output power: more than 70W (B1 band)
more than 60W (H5, H7 bands)

310

Enter the CCTM command 32 to place the radio in receive mode.

Enter the CCTM command 101 x x 0, where x is the highest
frequency (in hertz) for maximum power, as given in Table 11.8
(B1 band), Table 11.9 (H5) or Table 11.10 (H7).

Repeat Step 5 to Step 7.

10.

Remove the test lead and test capacitor, and resolder the blocking
capacitors C361, C362 and C363 (see Figure 11.27) in position.

11.

Transmitter Fault Finding (50W/40W Radios)

TM9100 Service Manual
© Tait Electronics Limited August 2005

Figure 11.28 Components of concern on the bottom-side of the main board (B1 band)

VCO BOT CAN

B1 BAND

TM9100 Service Manual
© Tait Electronics Limited August 2005

R390

R389

COPPER PLATE

NB BOT CAN

Transmitter Fault Finding (50W/40W Radios)

311

Figure 11.29 Components of concern on the bottom-side of the main board (H5 and H7 bands)

COPPER PLATE

VCO BOT CAN

R390

R389

R3000

H5, H7 BANDS

312

Transmitter Fault Finding (50W/40W Radios)

TM9100 Service Manual
© Tait Electronics Limited August 2005

Figure 11.30 Circuitry under the LPF TOP can

B1 BAND

TM9100 Service Manual
© Tait Electronics Limited August 2005

H5, H7 BANDS

Transmitter Fault Finding (50W/40W Radios)

313

Task 35 —
Check Components
of LPF

If there are no faults in the final RF signal path up to and including the PIN
switch, then the fault should lie in the LPF. Check the LPF as follows:
1.

If not already done, remove the LPF TOP can.

Connect the RF connector to the test set.

Check the capacitors and inductors of the LPF between the PIN
switch and the RF connector. See Figure 11.30. Check for shorts,
open circuits, and faulty components. Repair any fault.

In the case of the B1 band, replace the LPF TOP can before continuing.

Enter the CCTM command 326 5 to set the transmitter power level
to the maximum.

Enter the CCTM command 101 x x 0, where x is the lowest
frequency (in hertz) for maximum power, as given in Table 11.8
(B1 band), Table 11.9 (H5) or Table 11.10 (H7).

Enter the CCTM command 33 to place the radio in transmit mode.

Measure the RF output power. This should be:
RF output power: more than 70W (B1 band)
more than 60W (H5, H7 bands)

314

Enter the CCTM command 32 to place the radio in receive mode.

10.

Enter the CCTM command 101 x x 0, where x is the highest
frequency (in hertz) for maximum power, as given in Table 11.8
(B1 band), Table 11.9 (H5) or Table 11.10 (H7).

11.

Repeat Step 7 to Step 9.

12.

If the power in both the above cases exceeds 70W (B1) or 60W
(H5, H7), the fault has been rectified; go to “Final Tasks” on
page 147. If it does not, the repair failed; replace the main-board
assembly and go to “Final Tasks” on page 147.

Transmitter Fault Finding (50W/40W Radios)

TM9100 Service Manual
© Tait Electronics Limited August 2005

Transmitter Fault Finding (25W Radios)

Introduction

This section covers the diagnosis of faults in the transmitter circuitry for the
25W radios. The main indication of a fault in the transmitter is a reduction
in range. This implies that the power output is wrong or too low. Another
type of fault is manifested when the radio always transmits at full power, even
if set otherwise. Regardless of the fault, the lock status should be normal.

Fault-Diagnosis
Tasks

The procedure for diagnosing transmitter faults is divided into tasks, which
are grouped into the following sections:
■

“Power Supplies”

■

“Transmitter RF Power”

■

“Biasing of PA Driver and PAs”

■

“RF Signal Path”

Before beginning the fault diagnosis with “Power Supplies”, note the
following information regarding CCTM commands, frequency bands, can
removal and replacement, and transmit tests.
CCTM Commands

Table 12.1
Command

The CCTM commands required in this section are listed in Table 12.1.
Full details of the commands are given in “Computer-Controlled Test
Mode (CCTM)” on page 112.

CCTM commands required for the diagnosis of faults in the transmitter
Description

32
33
47
101 x y 0
114 x

304
304 x
318
319
326 x

331
331 x
332
332 x
334 x
335 x

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315

Frequency Bands

Some fault-diagnosis tasks require programming the radio with the lowest,
center or highest frequency in the radio’s frequency band. The relevant
frequencies for the different bands are listed in Table 12.2. Note that the
following frequency ranges are reserved worldwide for use by distress
beacons:
■

B1 band: 156.8MHz ± 375kHz

■

H5 band: 406.0 to 406.1MHz

Do not program the radio with any frequency in the above ranges.
Table 12.2
Band
B1
H5
H6

Can Removal

Lowest, center and highest frequencies in MHz
Lowest
frequency
136
400
450

Center
frequency
155
435
490

Highest
frequency
174
470
530

There are five cans shielding the bulk of the transmitter circuitry:
■

PAD TOP

■

PAF TOP

■

DIRC TOP

■

PIN TOP

■

LPF TOP

316

Replace all cans that have been removed only after repairing the board.
This applies to the B1, H5 and H6 bands. For certain other bands the
transmitter will not operate correctly unless all the cans are fitted.

Transmitter Fault Finding (25W Radios)

TM9100 Service Manual
© Tait Electronics Limited August 2005

Transmit Tests

The following points need to be borne in mind when carrying out transmit
tests:
■

secure main-board assembly

■

ensure proper antenna load

■

limit duration of transmit tests

■

protect against accidental transmissions

■

avoid thermal and RF burns

These points are discussed in more detail below.
Secure Main-Board
Assembly

Ensure Proper
Antenna Load

Limit Duration of
Transmit Tests

Protect Against
Accidental
Transmissions

Under certain circumstances the microprocessor can key on the transmitter.
Ensure that all instruments are protected at all times from such accidental
transmissions.

Avoid Thermal
and RF Burns

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317

12.1

Power Supplies
First check that a power supply is not the cause of the fault. There are two
power supplies and a switch circuit for the transmitter:

Introduction

■

Task 1: 13.8V DC supply from power connector (+13V8 BATT)

■

Task 2: switch circuit for 13.8V DC supply

■

Task 3: 9V DC supply from 9V regulator in PSU module (+9V0 TX)

The measurement and test points for diagnosing faults in the power supplies
are summarized in Figure 12.1.
Figure 12.1

Measurement and test points for diagnosing faults involving the power supplies for
the transmitter

+9V0 TX

TRANSMITTER
+13.8 V DC
+13.8 V DC SUPPLY
SUPPLY TO PAs
TO PA DRIVER

POWER
SUPPLY

9V0 TX
TEST POINT

+13V8 BATT
SIGNAL TYPES
RF
SWITCH

ANALOG

AGND
L310

L306
GND
TEST POINT

OTHER
TRANSMITTER
CIRCUITRY

318

PAs

DRIVER

Transmitter Fault Finding (25W Radios)

EXCITER

INTERFACE
CIRCUITRY

FREQUENCY
SYNTHESIZER

TM9100 Service Manual
© Tait Electronics Limited August 2005

Task 1 —
13.8V Power Supply

First check the power supply from the power connector.
1.

Obtain a needle probe to use for measurements of the power supply
at the PA driver and PAs. If none is available, remove the PAF TOP and
PAD TOP cans.

Set the DC power supply to 13.8V, with a current limit of 9A.

Enter the CCTM command 326 5 to set the radio to maximum
power.

Attempt to place the radio in transmit mode. Enter the CCTM
command 33.

If the radio enters the transmit mode, continue with Step 7. If instead
a C03 error is displayed in response to the command 33, go to Task 7
in “Transmitter RF Power” on page 328.

Measure the voltage at the point on L310 shown in Figure 12.2.
This is the supply at the common drain of Q309 and Q310, and
should be:
common drain of Q309 and Q310: more than 13V DC

Also measure the voltage at the point on L306 shown in
Figure 12.3. This is the supply at the drain of Q306, and should be:
drain of Q306: more than 13V DC

Enter the CCTM command 32 to place the radio in receive mode.

10.

If the power supply measured in Step 7 and Step 8 is not correct, go
to Task 2. If it is, go to Task 3.

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© Tait Electronics Limited August 2005

Transmitter Fault Finding (25W Radios)

319

Figure 12.2

Point for measuring the power supply to the PAs

B1 BAND
MEASUREMENT POINT ON L310
(B1 BAND SIMILAR)

H5, H6 BANDS

320

Transmitter Fault Finding (25W Radios)

TM9100 Service Manual
© Tait Electronics Limited August 2005

Figure 12.3

Point for measuring the power supply to the PA driver

POINT 1 ON R350

POINT 2 ON R350

B1 BAND

MEASUREMENT
POINT ON R339

MEASUREMENT
POINT ON L306

R324
C310

POINT 1 ON R350

POINT 2 ON R350

MEASUREMENT
POINT ON L306

L306

H5, H6 BANDS

TM9100 Service Manual
© Tait Electronics Limited August 2005

MEASUREMENT
POINT ON R339

Transmitter Fault Finding (25W Radios)

321

Task 2 —
Check Switch Circuit

If the power supply to the drains of the PAs and PA driver is not correct, the
switch circuit is suspect. Check the circuit as follows:
1.

Measure the voltage at the point 1 on R350 shown in Figure 12.3.
The voltage should be:
point 1 on R350: 13.8V DC

If the voltage measured in Step 1 is correct, go to Step 3. If it is not,
check for continuity between R350 and the power connector. Repair
any fault and conclude with Step 8.

Measure the voltage at R339 as shown in Figure 12.3. The voltage
should be:
R339: 9V DC

If the voltage measured in Step 3 is correct, go to Step 5. If it is not,
go to Task 3 and check the 9V power supply.

Measure the voltage at the point 2 on R350 shown in Figure 12.3.
The voltage should be:
point 2 on R350: < 5V DC

Task 3 —
9V Power Supply

If the voltage measured in Step 5 is correct, go to Step 7. If it is not,
replace Q308 — see Figure 12.3 — and conclude with Step 8.

If the supply from the power connector is correct, check the 9V DC supply.
1.

Enter the CCTM command 326 1 to set the transmitter power level
very low.

Enter the CCTM command 33 to place the radio in transmit mode.

Measure the supply voltage between the 9V0 TX test point and the
GND test point (see Figure 12.4).
supply 9V0 TX: 9.0 ± 0.5V DC

322

Enter the CCTM command 32 to place the radio in receive mode.

If the supply measured in Step 3 is correct, go to Task 4 in
“Transmitter RF Power” on page 326. If it is not, the 9V regulator
IC601 and the associated switching circuitry Q603 are suspect; go to
Task 3 of “Power Supply Fault Finding” on page 158.

Transmitter Fault Finding (25W Radios)

TM9100 Service Manual
© Tait Electronics Limited August 2005

Figure 12.4

Test points for checking the 9V supply, the forward and reverse RF power, and the
inhibiting of the transmitter

VCO TOP CAN (UHF ONLY)

DIRC TOP CAN

D TX INH
TEST POINT

REV PWR
TEST POINT

TX INH
TEST POINT

FWD PWR
TEST POINT

IF TOP CAN
9V0 TX TEST POINT

GND TEST POINT

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12.2

Transmitter RF Power

Introduction

If there is no fault with the power supplies, check the transmitter RF power
and correct any fault. The procedure is covered in the following eight tasks:
■

Task 4: check forward and reverse powers

■

Task 5: check RF output power

■

Task 6: power unchanged regardless of setting

■

Task 7: check for inhibiting of transmitter

■

Task 8: check temperature sensor

■

Task 9: power and current are skewed

■

Task 10: repair output matching circuitry

■

Task 11: power and current are low

The measurement points for diagnosing faults concerning the transmitter
RF power are summarized in Figure 12.5. Data required for the first task
(checking the forward and reverse powers) are supplied in Table 12.3.
Table 12.3

Voltages in millivolts corresponding to nominal forward and reverse powers

Frequency band

Forward power (318 command)

Reverse power (319 command)

1100 to 2000

< 500

2500 to 3500

< 1000

2800 to 3900

< 1000

324

Transmitter Fault Finding (25W Radios)

TM9100 Service Manual
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LEAD TO
TEST SET

RF CONNECTOR

LPF

DIGITAL

CLOCK

ANALOG

SIGNAL TYPES

REV PWR
TEST POINT

RECEIVER

PIN SWITCH

BUFFER
AMPLIFIER

FWD PWR
TEST POINT

DIRECTIONAL
COUPLER

50 Ω TEST LEAD
TO TEST SET

DIGITAL
BOARD

POWER
CONTROL

SYN LOCK

DIG SYN EN

DIG TX INH

D TX INH
TEST POINT

PAs
DRIVER

AND

CDC TX FIN BIAS2

CDC TX PWR CTL

SHAPER
AND
LEVEL
SHIFTER

SHAPING
FILTER

TX REV PWR

TX FWD PWR

CDC TX FIN BIAS1

CDC TX DRV BIAS

SYN TX LO

SHAPER
AND
LEVEL
SHIFTER

BIAS
LIMITER

EXCITER

OR GATE

TX INH
TEST POINT

CODEC
AND AUDIO
CIRCUITRY

FREQUENCY
SYNTHESIZER

Figure 12.5
Measurement and test points for diagnosing faults concerning the transmitter
RF power

Transmitter Fault Finding (25W Radios)

325

Task 4 —
Check Forward and
Reverse Powers

First check the forward and reverse powers for an indication of which part
of the circuitry is suspect.
1.

Enter the CCTM command 326 4 to set the transmitter power level
high.

Enter the CCTM command 33 to place the radio in transmit mode.

Enter the CCTM command 318 to check the forward power.
The value returned is the voltage in millivolts corresponding to the
power level, and should be as shown in Table 12.3.

Confirm the above result by checking the level at the FWD PWR test
point (see Figure 12.4) using an oscilloscope.

Enter the CCTM command 319 to check the reverse power.
The value returned is the voltage in millivolts corresponding to the
power level, and should be as shown in Table 12.3.

Confirm the above result by checking the level at the REV PWR test
point (see Figure 12.4) using an oscilloscope.
If the oscilloscope momentarily indicates a very high reverse power,
then the most likely scenario is that the antenna VSWR threshold has
been exceeded and the PA has shut down to very low power.

326

Enter the CCTM command 32 to place the radio in receive mode.

If the values obtained in Step 3 and Step 5 are both correct, and there
is no indication of a momentary high reverse power, go to Task 5.
If one or both are incorrect, go to Step 9.

Check the connection from the RF connector on the radio to the test
set.

10.

If there is no fault, go to Step 11. If there is, rectify the fault and
repeat the above measurements.

11.

If the reverse power is momentarily too high, the directional coupler,
PIN switch or LPF is suspect; go to Task 29. Otherwise go to Task 5.

Transmitter Fault Finding (25W Radios)

TM9100 Service Manual
© Tait Electronics Limited August 2005

Task 5 —
Check RF Output
Power

If the power supplies are correct, check the RF output power of the
transmitter.
1.

Enter the CCTM command 326 5 to set the transmitter power level
to the maximum value.

Enter the CCTM command 33 to place the radio in transmit mode.

Note the RF output power measured by the test set, and note the
current reading on the DC power supply.
RF output power: > 30W
current: < 8A (VHF), < 9A (UHF)

Table 12.4

Enter the CCTM command 32 to place the radio in receive mode.

Repeat Step 3 to Step 5.

10.

Depending on the results of the above measurements, proceed to the
task indicated in Table 12.4. Note that the power and current are
considered to be skewed if they are low at one part of the frequency
band and high elsewhere.

Tasks to be performed according to the results of the power and current measurements
of Task 5

Power

Current

Task

Correct

Task 6 — Power unchanged regardless of setting

Correct

Wrong

Task 29 — Check power at directional coupler

Skewed

Task 9 — Power and current are skewed

Low (> 0.1W)

Low (> 0.5A)

Task 11 — Power and current are low

None at RF connector (< 0.1W)

Low (> 0.5A)

Task 29 — Check power at directional coupler

None at RF connector (< 0.1W)

None (< 0.5A)

Task 7 — Check for inhibiting of transmitter

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Transmitter Fault Finding (25W Radios)

327

Task 6 —
Power Unchanged
Regardless of
Setting

If all the power and current values measured in Task 5 are correct, it is likely
that the power remains unchanged regardless of the power setting.
1.

Task 7 —
Check for Inhibiting
of Transmitter

Enter the following CCTM commands in turn and measure the RF
output power in each case:
■

326 4

■

326 3

■

326 2

■

326 1

The above measurements should confirm that the power remains
unchanged at all settings. Carry out Task 12 and then Task 19.

If the transmitter is drawing no current or the wrong current, check
whether it is being inhibited. This check is also required if a CO3 error
occurs in Task 1.
1.

If not already done, enter the CCTM command 33 to place the radio
in transmit mode.

Check the logic signal at the TX INH test point (see Figure 12.4).
The signal should be:
TX INH test point: about 0V (inactive)

If the signal is inactive as required, go to Step 4. If it is active — about
1.1V — the transmitter is being inhibited; go to Step 5.

Enter the CCTM command 32 to place the radio in receive mode,
and go to Task 12 in “Biasing of PA Driver and PAs” on page 335.

Check the logic signal at the D TX INH test point (see Figure 12.4).
The signal should be:
D TX INH test point: about 0V (inactive)

328

If the signal is inactive as required, go to Step 8. If it is active — about
3.2V — the temperature sensor is suspect; go to Step 7.

Enter the CCTM command 32 to place the radio in receive mode,
and go to Task 8.

The lock status is possibly no longer normal. Enter the CCTM
command 72 and check the lock status.

Enter the CCTM command 32 to place the radio in receive mode.

10.

The normal lock status is 110. If it is not, proceed to the relevant
section. If it is, go to Step 11.

11.

Check for short circuits on the DIG TX INH line from the D TX INH test
point.

Transmitter Fault Finding (25W Radios)

TM9100 Service Manual
© Tait Electronics Limited August 2005

12.

Task 8 —
Check Temperature
Sensor

If the transmitter is being inhibited and the logic signal at the D TX INH test
point is active, a fault in the temperature sensor might be the cause.
1.

Enter the CCTM command 47 to check the temperature reading.

Of the two numbers returned, the first is the temperature in degrees
celsius and should be about 25°C. If it is, go to Task 12 in “Biasing of
PA Driver and PAs” on page 335. If it is not, go to Step 3.

If not already done, remove the PAF TOP can.

Check D301 and the surrounding components — see Figure 12.6
(B1 band) and Figure 12.7 (H5 and H6 bands).

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Transmitter Fault Finding (25W Radios)

329

Figure 12.6

PA circuitry under the PAF TOP can and part of the directional coupler under the DIRC TOP
can (B1 band)

Temperature
sensor
Mounting point
for test capacitor

Test pad

330

Transmitter Fault Finding (25W Radios)

TM9100 Service Manual
© Tait Electronics Limited August 2005

Figure 12.7

PA circuitry under the PAF TOP can and part of the directional coupler under the DIRC TOP
can (H5 and H6 bands)

Temperature
sensor

Mounting point
for test capacitor

Test pad

Transmitter Fault Finding (25W Radios)

331

Task 9 —
Power and Current
Are Skewed

If the RF output power and the supply current are skewed, the output
matching is suspect.
1.

Remove the DIRC TOP can.

Remove the coupling capacitors C348, C349 and C350 —
see Figure 12.6 (B1), and Figure 12.7 (H5, H6).

Solder one terminal of an 82pF (H5, H6 bands) or 680pF (B1) test
capacitor to the PCB at the point shown in Figure 12.6 to
Figure 12.7. Mount the capacitor vertically. Use a test capacitor of
the type GRM111, DLI C17, Murata 1210, or the equivalent.

Solder a 50Ω test lead to the PCB. Solder the outer sheath to the test
pad shown in Figure 12.6 to Figure 12.7, and solder the central
wire to the other terminal of the test capacitor.

Connect the test lead to the test set.

Program the radio with the highest frequency in the radio’s frequency
band: Enter the CCTM command 101 x x 0, where x is the frequency
in hertz.

Enter the CCTM command 33 to place the radio in transmit mode.

Note the RF output power measured by the test set, and note the
current reading on the DC power supply.
RF output power: > 35W
current: < 8A (VHF), < 9A (UHF)

332

Enter the CCTM command 32 to place the radio in receive mode.

10.

Program the radio with the center frequency in the band: Enter the
CCTM command 101 x x 0, where x is the frequency in hertz.

11.

Repeat Step 7 to Step 9.

12.

Program the radio with the lowest frequency in the band: Enter the
CCTM command 101 x x 0, where x is the frequency in hertz.

13.

Repeat Step 7 to Step 9.

14.

Transmitter Fault Finding (25W Radios)

Task 10 —
Repair Output
Matching Circuitry

If the checks in Task 9 show that the power and current are still skewed,
there is a fault in the output matching circuitry.
1.

If not already done, remove the PAF TOP can.

Check for faulty, shorted or misplaced components in the circuit
between the test capacitor and the common drain of Q309 and Q310
(see Figure 12.6 to Figure 12.7). Repair any fault.

Program the radio with the highest frequency in the radio’s frequency
band: Enter the CCTM command 101 x x 0, where x is the frequency
in hertz.

Enter the CCTM command 33 to place the radio in transmit mode.

Note the RF output power measured by the test set, and note the
current reading on the DC power supply.
RF output power: > 35W
current: < 8A (VHF), < 9A (UHF)

Enter the CCTM command 32 to place the radio in receive mode.

Program the radio with the center frequency in the band: Enter the
CCTM command 101 x x 0, where x is the frequency in hertz.

Repeat Step 4 to Step 6.

Program the radio with the lowest frequency in the band: Enter the
CCTM command 101 x x 0, where x is the frequency in hertz.

10.

Repeat Step 4 to Step 6.

11.

Remove the test lead and test capacitor, and resolder the coupling
capacitors C348, C349 and C350 in position (see Figure 12.6 to
Figure 12.7).

12.

If the power and current are now correct at all three frequencies, the
fault has been rectified; go to “Final Tasks” on page 147. If they are
not, go to Task 25 in “RF Signal Path” on page 355.

Transmitter Fault Finding (25W Radios)

333

Task 11 —
Power and Current
Are Low

Table 12.5

If the RF output power and the supply current are uniformly low at all
frequencies, one of the PAs is suspect or the input to the PAs is reduced.
Check each PA in turn:
1.

For the first PA (Q310), enter the CCTM command 331 to check the
DAC value of final bias 1 (CDC TX FIN BIAS 1). Record the value x
returned.

Note the current reading on the DC power supply.

Enter the CCTM command 331 1 to turn off final bias 1.

Enter the CCTM command 33 to place the radio in transmit mode.

Note the RF output power measured at the test set. This should be
as shown in Table 12.5.

If the RF power is correct, go to Step 7 to repeat the check with the
second PA. If it is not, enter the CCTM command 32 to place the
radio in receive mode, and carry out Task 12 and then Task 13.

For the second PA (Q309), enter the CCTM command 332 to check
the DAC value of final bias 2 (CDC TX FIN BIAS 2). Record the value y
returned.

Note the current reading on the DC power supply.

Enter the CCTM command 332 1 to turn off final bias 2.

10.

With the radio still in transmit mode, note the RF output power
measured at the test set. This should be as shown in Table 12.5.

11.

Enter the CCTM command 32 to place the radio in receive mode.

12.

If the RF power measured in Step 10 is correct, go to “RF Signal
Path” on page 354. If it is not, carry out Task 12 and then Task 16.

RF output power of individual RF power amplifiers at different frequencies
Frequency within band

Frequency band
Lowest frequency

Center frequency

Highest frequency

29 ± 5W

34 ± 5W

29 ± 5W

5 ± 5W

12 ± 5W

27 ± 5W

13 ± 5W

19 ± 5W

28 ± 5W

334

Transmitter Fault Finding (25W Radios)

12.3

Biasing of PA Driver and PAs

Introduction

Task 12: prepare to check biasing

■

Task 13 to Task 15: check biasing of first PA

■

Task 16 to Task 18: check biasing of second PA

■

Task 19 and Task 20: check biasing of PA driver

■

Task 21 to Task 24: repair circuitry

The test and measurement points for diagnosing faults in the biasing of the
PAs and PA driver are summarized in Figure 12.8.
Task 12 —
Prepare to
Check Biasing

If the transmitter is not being inhibited, check the biasing of the two PAs
and the PA driver. First make the following preparations:
1.

Set the current limit on the DC power supply to 2A.

Enter the CCTM command 331 to check the DAC value of final bias
1 (CDC TX FIN BIAS 1) at maximum power. Record the value x returned.

Enter the CCTM command 332 to check the DAC value of final bias
2 (CDC TX FIN BIAS 2) at maximum power. Record the value y returned.

Enter the CCTM command 304 to check the DAC value of the
clamp current at the driver gate. Record the value z returned.

Enter the CCTM command 33 to place the radio in transmit mode.

Switch off all biases by entering the following CCTM commands in
sequence:
■

331 1

■

332 1

■

304 1

■

114 1023

■

334 0

■

335 0

Note the current reading on the DC power supply. This will be less
than 500mA.

With the radio still in transmit mode, check the biasing of the PAs and
PA driver, beginning with Task 13.

Transmitter Fault Finding (25W Radios)

335

336

Transmitter Fault Finding (25W Radios)

ANALOG

SIGNAL TYPES

PIN
SWITCH
AND LPF

BUFFER
AMPLIFIER

PIN 5 OF
IC303

DIRECTIONAL
COUPLER

PIN 10 OF
IC303

R347

PIN 9 OF
IC303

POWER
CONTROL

R336

PIN 8 OF
IC303

GATES OF
Q309, Q310

PAs

SHAPING
FILTER

SHAPER
AND
LEVEL
SHIFTER
PIN 8 OF
IC301

PIN 1 OF
IC301

SHAPER
AND
LEVEL
SHIFTER

BIAS
LIMITER

EXCITER

PIN 14 OF
IC301

SET PWR
TEST POINT

DRIVER

GATE OF
Q306

TX REV PWR

TX FWD PWR

CDC TX PWR CTL

PWR
TEST POINT

CDC TX FIN BIAS2

FIN2
TEST POINT

CDC TX FIN BIAS1

FIN1
TEST POINT

CDC TX DRV BIAS

DRV
TEST POINT

CODEC
AND AUDIO
CIRCUITRY

FREQUENCY
SYNTHESIZER

Figure 12.8
Measurement and test points for diagnosing faults in the biasing of the PAs and PA
driver

Task 13 —
Check Biasing
of First PA

Check the biasing of the first PA (Q310).
Important

Ensure that the current limit on the DC supply is 2A.
And, when entering the CCTM command 331 x, do not
specify a value x higher than that recorded in Task 12.
Failure to do so might result in the destruction of the PAs.

Use a multimeter to measure the voltage at pin 14 of IC301
(see Figure 12.9). The voltage should be:
pin 14 of IC301: < 100mV (initially)

Note the current reading on the DC power supply. As mentioned in
Step 7 of Task 12, this will be less than 500mA.

Enter the CCTM command 331 x (where x was recorded in Task 12).

Check that the voltage changes to:
pin 14 of IC301: 2 to 5V (after entry of CCTM 331 x)

Table 12.6

Also note the current reading. This should increase by an amount
approximately equal to the offset given in Table 12.6.

If the voltage and current are both correct, go to Step 7. If the voltage
is correct but not the current, go to Task 14. If neither the current
nor the voltage is correct, go to Task 15.

Enter the CCTM command 331 1 to switch off final bias 1, and go to
Task 16.

Gate biases for the PAs and PA driver at high power
Offset currents in mA

Frequency band
First PA

Second PA

PA driver

750

300

1000

450

1000

450

Transmitter Fault Finding (25W Radios)

337

Figure 12.9

Test points and components of the shaping filter

VCO TOP CAN (UHF ONLY)

DIRC TOP CAN

SET PWR
TEST POINT

DRV TEST POINT

FWD PWR
TEST POINT
IF TOP CAN

PWR TEST POINT

338

FIN1 TEST POINT

Transmitter Fault Finding (25W Radios)

FIN2 TEST POINT

Task 14 —
Shaper and
Level Shifter

If the voltage measured in Task 13 is correct but not the current, either the
first PA or the shaper and level shifter for the PA is suspect.
Important

If the PAF TOP can has already been removed, go to Step 5. If it has not,
go to Step 2.

Enter the CCTM command 32 to place the radio in receive mode.

Remove the PAF TOP can.

Enter the CCTM command 33 to place the radio in transmit mode.

Enter the CCTM command 331 x (where x was recorded in Task 12).

Check that the voltage at the gate of Q310 is (see Figure 12.10):
gate of Q310: 2 to 5V

Enter the CCTM command 32 to place the radio in receive mode.

If the voltage measured above is correct, Q310 is faulty; replace the
main-board assembly and go to “Final Tasks” on page 147. If it is not
correct, go to Step 9.

Check the circuitry between pin 14 of IC301 and the gate of Q310
(see Figure 12.10). If a fault is found, repair it, confirm the removal
of the fault, and go to “Final Tasks” on page 147. If the repair failed
or Q310 itself is faulty, replace the main-board assembly and go to
“Final Tasks” on page 147.

Transmitter Fault Finding (25W Radios)

339

Figure 12.10 PA circuitry under the PAF TOP can

B1 BAND

CICUITRY BETWEEN IC301 AND PAs
(H5 AND H6 BANDS SIMILAR)

PAF TOP

VIA TO PIN 14 OF IC301

VIA TO PIN 8 OF IC301

VIA TO GATE OF Q309

VIA TO GATE OF Q310

H5, H6 BANDS

PAF TOP

340

Transmitter Fault Finding (25W Radios)

Task 15 —
Shaping Filter for
Power Control

If neither the voltage nor the current measured in Task 13 is correct, then
the shaping filter for the power-control circuitry or the CODEC and audio
circuitry is suspect.
Important

Use the multimeter to measure the voltage at the FIN1 test point
(see Figure 12.9). The voltage should be:
FIN1 test point: 18 ± 2mV (initially)

Enter the CCTM command 331 x (where x was recorded in Task 12).

Check that the voltage changes to:
FIN1 test point: 1.1 to 2.7V (after entry of CCTM 331 x)

Enter the CCTM command 32 to place the radio in receive mode.

If the voltage measured above is correct, go to Step 6. If it is not, go
to “CODEC and Audio Fault Finding” on page 371.

Check IC301 and the surrounding shaping-filter circuitry
(see Figure 12.9). If a fault is found, repair it, confirm the removal
of the fault, and go to “Final Tasks” on page 147. If the repair failed,
replace the main-board assembly and go to “Final Tasks” on
page 147.

Transmitter Fault Finding (25W Radios)

341

Task 16 —
Check Biasing
of Second PA

If the biasing of the first PA is correct, check that of the second PA (Q309).
Important

Ensure that the current limit on the DC supply is 2A.
And, when entering the CCTM command 332 y, do not
specify a value y higher than that recorded in Task 12.
Failure to do so might result in the destruction of the PAs.

Use the multimeter to measure the voltage at pin 8 of IC301
(see Figure 12.9). The voltage should be:
pin 8 of IC301: < 100mV (initially)

Note the current reading on the DC power supply. As mentioned in
Step 7 of Task 12, the current will be less than 500mA.

Enter the CCTM command 332 y (where y was recorded in Task 12).

Check that the voltage changes to:
pin 8 of IC301: 2 to 5V (after entry of CCTM 332 y)

342

Also note the current reading. This should increase by an amount
approximately equal to the offset given in Table 12.6.

If the voltage and current are both correct, go to Step 7. If the voltage
is correct but not the current, go to Task 17. If neither the current
nor the voltage is correct, go to Task 18.

Enter the CCTM command 332 1 to switch off final bias 2, and go to
Task 19.

Transmitter Fault Finding (25W Radios)

Task 17 —
Shaper and
Level Shifter

If the voltage measured in Task 16 is correct but not the current, either the
second PA or the shaper and level shifter for the PA is suspect.
Important

If the PAF TOP can has already been removed, go to Step 5. If it has not,
go to Step 2.

Enter the CCTM command 32 to place the radio in receive mode.

Remove the PAF TOP can.

Enter the CCTM command 33 to place the radio in transmit mode.

Enter the CCTM command 332 y (where y was recorded in Task 12).

Check that the voltage at the gate of Q309 is (see Figure 12.10):
gate of Q309: 2 to 5V

Enter the CCTM command 32 to place the radio in receive mode.

If the voltage is correct, Q309 is faulty; replace the main-board
assembly and go to “Final Tasks” on page 147. If it is not, go to
Step 9.

Check the circuitry between pin 8 of IC301 and the gate of Q309
(see Figure 12.10). If a fault is found, repair it, confirm the removal
of the fault, and go to “Final Tasks” on page 147. If the repair failed
or Q309 itself is faulty, replace the main-board assembly and go to
“Final Tasks” on page 147.

Transmitter Fault Finding (25W Radios)

343

Task 18 —
Shaping Filter for
Power Control

If neither the voltage nor the current measured in Task 16 is correct, then
the shaping filter for the power-control circuitry or the CODEC and audio
circuitry is suspect.
Important

Use the multimeter to measure the voltage at the FIN2 test point
(see Figure 12.9). The voltage should be:
FIN2 test point: 18 ± 2V (initially)

Enter the CCTM command 332 y (where y was recorded in Task 12).

Check that the voltage changes to:
FIN2 test point: 1.1 to 2.7V (after entry of CCTM 332 y)

344

Enter the CCTM command 32 to place the radio in receive mode.

If the voltage measured above is correct, go to Step 6. If it is not, go
to “CODEC and Audio Fault Finding” on page 371.

Transmitter Fault Finding (25W Radios)

Task 19 —
Biasing of
PA Driver—
DRV test point

If there is no fault in the biasing of the PAs, investigate the biasing of the PA
driver (Q306). First check the DRV test point.
Important

Ensure that the current limit on the DC supply is 2A.
And, when entering the CCTM command 304 z, do not
specify a value z higher than that recorded in Task 12.
Failure to do so might result in the destruction of the PA
driver.

Note the current reading on the DC power supply. As mentioned in
Step 7 of Task 12, the current will be less than 500mA.

Enter the CCTM command 304 z (where z was recorded in Task 12)
to switch on the clamp current.

Note the current reading on the DC power supply.

Compare the above current readings. The current should increase by
an amount approximately equal to the offset given in Table 12.6.
If it does, go to Task 21. If it does not, go to Step 5.

Check as follows that the voltage from the DAC is changing:
First enter the CCTM command 304 1 to switch off the bias.

Measure the voltage at the DRV test point (CDC TX DRV BIAS)
(see Figure 12.9). The voltage should be:
DRV test point: < 0.1V (after entry of CCTM 304 1)

Enter the CCTM command 304 z (where z was recorded in Task 12)
to change the DAC value of the clamp current.

The voltage should increase to:
DRV test point: 0.8 to 2.5V (after entry of CCTM 304 z)

If the voltage does change, go to Task 20. If it does not, go to
Step 10.

10.

Enter the CCTM command 32 to place the radio in receive mode,
and go to “CODEC and Audio Fault Finding” on page 371.

Transmitter Fault Finding (25W Radios)

345

Task 20 —
Biasing of
PA Driver—
SET PWR test point

If the voltage at the DRV test point is correct, check that at the SET PWR test
point.
1.

Check the voltage at the SET PWR test point (see Figure 12.9):
SET PWR test point: 2 to5V

If the voltage is correct, go to Step 3. If it is not, go to Task 21.

If the PAD TOP can has already been removed, go to Step 7. If it has
not, go to Step 4.

Enter the CCTM command 32 to place the radio in receive mode.

Remove the PAD TOP can.

Enter the CCTM command 33 to place the radio in transmit mode.

Check the voltage on the gate of Q306 (see Figure 12.11):
gate of Q306: 2 to 5V

346

Enter the CCTM command 32 to place the radio in receive mode.

If the voltage is correct, replace Q306; confirm the removal of the
fault and go to “Final Tasks” on page 147. If it is not, go to Task 23.

Transmitter Fault Finding (25W Radios)

Figure 12.11 PA driver circuitry under the PAD TOP can

COMPONENTS
C310, R324, R327

GATE OF Q306

B1 BAND

COMPONENTS
C310, R324, R327

GATE OF Q306

H5, H6 BANDS

Transmitter Fault Finding (25W Radios)

347

Task 21 —
Check Power
Control

Check the power-control circuitry if the clamp current for the PA driver is
correct or if the voltage at the SET PWR test point is incorrect.
Important

Ensure that the current limit on the DC supply is 2A.
And, when entering the CCTM command 304 z, do not
specify a value z higher than that recorded in Task 12. Failure to do so might result in the destruction of the PA driver.

Enter the CCTM command 304 z (where z was recorded in Task 12).

Note the current reading on the DC power supply.

Enter the CCTM command 114 0 to switch off the power.

Note the current reading on the DC power supply.

Compare the above current readings. The current should decrease by
an amount approximately equal to the offset given in Table 12.6.
If it does, go to Task 25 in “RF Signal Path” on page 355. If it does
not, go to Step 6.

Check that the voltage from the DAC is changing. Measure the
voltage at the PWR test point (CDC TX PWR CTL) (see Figure 12.9).

Enter the CCTM command 114 1023. The voltage should increase
to:
PWR test point: 2.4 ± 0.1V

348

Enter the CCTM command 32 to place the radio in receive mode.

If the voltage at the PWR test point increases as required, go to
Task 22. If it does not, go to “CODEC and Audio Fault Finding” on
page 371.

Transmitter Fault Finding (25W Radios)

Figure 12.12 Circuitry under the DIRC TOP can
B1 band

H5/H6 bands

Transmitter Fault Finding (25W Radios)

349

Task 22 —
Directional Coupler
and Buffer
Amplifier

Table 12.7

Cycle the power.

Enter the CCTM command 326 5 to set the transmitter to maximum
power.

Enter the CCTM command 33 to place the radio in transmit mode.

Measure the voltage at pin 9 of IC303 in the power-control circuit
(see Figure 12.9).

The above voltage should be as given in Table 12.7. If it is, go to
Task 24. If it is not, go to Step 6.

Check the voltage at pin 5 of IC303 (or use the FWD PWR test point)
(see Figure 12.9). Note that the probe impedance might affect the
measurement.

Enter the CCTM command 32 to place the radio in receive mode.

The voltage measured in Step 6 should be as given in Table 12.7.
If it is not, go to Step 9. If it is, go to Step 11.

Voltages at IC303 at maximum power (40 W)
Voltage (V)

Frequency band

Frequency (MHz)
Pin 9

Pin 5 (FWD PWR)

136
155
174

2.2 ± 0.5
2.3 ± 0.5
2.5 ± 0.5

1.9 ± 0.5
2.1 ± 0.5
2.3 ± 0.5

400
435
470

3.4 ± 0.5
3.8 ± 0.5
4.0 ± 0.5

3.3 ± 0.5
3.7 ± 0.5
3.9 ± 0.5

450
490
530

3.9 ± 0.5
4.2 ± 0.5
4.7 ± 0.5

3.8 ± 0.5
4.1 ± 0.5
4.6 ± 0.5

350

Remove the DIRC TOP can.

10.

Check the components of the directional coupler (see Figure 12.12)
and go to Step 12.

11.

Check R340 between pins 6 and 7 of IC303 in the buffer amplifier
(see Figure 12.13), and then go to Step 12.

12.

Repair any fault revealed by the above checks. Replace IC303 if none
of the other components is faulty (see Figure 12.9).

Transmitter Fault Finding (25W Radios)

13.

Task 23 —
Power Control
for PA Driver

Confirm the removal of the fault and go to “Final Tasks” on
page 147. If the repair failed, replace the main-board assembly and go
to “Final Tasks” on page 147.

In this task any faults in the path between the power-control circuit and the
PA driver will be located, as well as any fault with the PA driver.
1.

Check for short circuits at the gate of the PA driver Q306. Check
R333, R336 (see Figure 12.9), C310, R324 and R327
(see Figure 12.11) between the power-control circuit and Q306.

Repair any fault revealed by the checks in Step 1. If none of the
above-mentioned components is faulty, replace Q306
(see Figure 12.11).

Confirm the removal of the fault and go to “Final Tasks” on
page 147. If the repair failed, replace the main-board assembly and go
to “Final Tasks” on page 147.

Transmitter Fault Finding (25W Radios)

351

Figure 12.13 Components of concern on the bottom-side of the main board
B1 band

H5/H6 bands

352

Transmitter Fault Finding (25W Radios)

Task 24 —
Power Control
and Shaping Filter

In this task any faults in the power-control and shaping-filter circuitry will
be located:
1.

Measure the voltage at pin 8 of IC303 (see Figure 12.9) in the
power-control circuit. The voltage should be:
pin 8 of IC303: 7.4 ± 0.5V

If the voltage is correct, go to Step 3. If it is not, enter the CCTM
command 32 and return to Task 23.

Measure the voltage at pin 10 of IC303 (see Figure 12.9) in the
power-control circuit. The voltage should be:
pin 10 of IC303: 4.8 ± 0.5V

If the voltage is correct, go to Step 5. If it is not, go to Step 8.

Enter the CCTM command 32 to place the radio in receive mode.

Check C322, C324, R342, R347 (see Figure 12.9) in the powercontrol circuit.

Repair any fault revealed by the checks in Step 5. Replace IC303
(see Figure 12.9) if none of the other components is faulty. Confirm
the removal of the fault and go to “Final Tasks” on page 147. If the
repair failed, replace the main-board assembly and go to “Final Tasks”
on page 147.

Measure the voltage at pin 1 of IC301 (see Figure 12.9) in the
shaping-filter circuit. The voltage should be:
pin 1 of IC301: 4.8 ± 0.5V

Enter the CCTM command 32 to place the radio in receive mode.

10.

If the voltage measured in Step 8 is correct, go to Step 11. If it is not,
go to Step 12.

11.

Check the components R334 (see Figure 12.9) and C319
(see Figure 12.13) and go to Step 13.

12.

Check the components between the PWR test point and pin 1 of
IC301 (see Figure 12.9) and go to Step 13.

13.

Repair any fault revealed by the checks in Step 11 and Step 12.
Replace IC301 (see Figure 12.9) if none of the other components
is faulty. Confirm the removal of the fault and go to “Final Tasks” on
page 147. If the repair failed, replace the main-board assembly and go
to “Final Tasks” on page 147.

Transmitter Fault Finding (25W Radios)

353

12.4

Introduction

■

Task 25 to Task 28: initial RF signal path

■

Task 29 and Task 30: directional coupler

■

Task 31 and Task 32: PIN switch

■

Task 33: LPF

The initial signal path includes the exciter and PA driver. The directional
coupler, PIN switch, and LPF make up the final signal path.
The measurement points for diagnosing faults in the signal path are
summarized in Figure 12.14.
Figure 12.14 Measurement points for diagnosing faults in the RF signal path
SIGNAL TYPES

SYNTHESIZER
OUTPUT
SYN TX LO

EXCITER
OUTPUT

RF
ANALOG

PAs

DRIVER

EXCITER
C301

L314

C300

TEST
CAPACITOR
GATES OF
Q309, Q310

50 Ω TEST
LEAD TO
TEST SET

PA DRIVER
OUTPUT AT
DRAIN OF Q306

BUFFER
OUTPUT
AT C313

FREQUENCY
SYNTHESIZER

DIRECTIONAL
COUPLER

RECEIVER
PIN
SWITCH
TEST
CAPACITOR
50 Ω TEST
LEAD TO
TEST SET

RF CONNECTOR

354

LPF

Transmitter Fault Finding (25W Radios)

Task 25 —
Output of
Frequency
Synthesizer

The first point to check in the initial RF signal path is the output SYN TX LO
from the frequency synthesizer. This signal is input to the exciter at C300.
1.

For test purposes select a representative power level and frequency
from Table 12.8 (B1 band) or Table 12.9 (H5, H6). (Note that the
data for these tables were obtained using an RFP5401A RF probe.)

To set the power level, enter the CCTM command 326 x, where x
defines the level. To set the frequency, enter the CCTM command
101 x x 0, where x is the frequency in hertz.

Enter the CCTM command 33 to place the radio in transmit mode.

Use an RFP5401A RF probe or the equivalent to measure the RF
voltage after C300 (see Figure 12.15). Earth the probe to the FCL TOP
can adjacent to the PA driver circuitry. The required voltage should
be as given in Table 12.8 (B1 band) or Table 12.9 (H5, H6).

Enter the CCTM command 32 to place the radio in receive mode.

If the voltage measured above is correct, go to Task 26. If it is not, go
to Step 7.

Check C300 (see Figure 12.15). If C300 is not faulty, go to
“Frequency Synthesizer Fault Finding” on page 169. If C300 is
faulty, replace it and return to Step 2.

Transmitter Fault Finding (25W Radios)

355

Figure 12.15 PA driver circuitry under the PAD TOP can

DRIVER OUTPUT

EXCITER OUTPUT AT C301

B1 BAND
BUFFER OUTPUT AT C313
SYNTHESIZER OUTPUT AT C300

EXCITER OUTPUT AT C301

DRIVER OUTPUT

H5, H6 BANDS
BUFFER OUTPUT AT C313
SYNTHESIZER OUTPUT AT C300

356

Transmitter Fault Finding (25W Radios)

Table 12.8

RF voltages along the initial RF signal path of the VHF radio (B1 band)
RF voltages (V)

Power level
(W)

Frequency
(MHz)

Synthesizer
output

Buffer
output

Exciter
output

Driver
output

136
155
174

0.3 ± 0.1
0.3 ± 0.1
0.2 ± 0.1

0.2 ± 0.1
0.3 ± 0.1
0.2 ± 0.1

2.4 ± 0.5
2.5 ± 0.5
2.6 ± 0.5

1.8 ± 0.5
1.0 ± 0.5
1.5 ± 0.5

136
155
174

0.3 ± 0.1
0.2 ± 0.1
0.2 ± 0.1

0.2 ± 0.1
0.3 ± 0.1
0.2 ± 0.1

2.5 ± 0.5
2.6 ± 0.5
2.6 ± 0.5

3.0 ± 0.5
1.5 ± 0.5
2.6 ± 0.5

136
155
174

0.3 ± 0.1
0.2 ± 0.1
0.2 ± 0.1

0.2 ± 0.1
0.3 ± 0.1
0.3 ± 0.1

2.5 ± 0.5
2.6 ± 0.5
2.7 ± 0.5

4.2 ± 0.5
2.0 ± 0.5
3.8 ± 0.5

136
155
174

0.3 ± 0.1
0.2 ± 0.1
0.2 ± 0.1

0.2 ± 0.1
0.3 ± 0.1
0.3 ± 0.1

2.4 ± 0.5
2.4 ± 0.5
2.5 ± 0.5

3.3 ± 0.5
1.7 ± 0.5
4.5 ± 0.5

136
155
174

0.3 ± 0.1
0.2 ± 0.1
0.3 ± 0.1

0.4 ± 0.1
0.4 ± 0.1
0.3 ± 0.1

2.5 ± 0.5
2.5 ± 0.5
2.5 ± 0.5

8.2 ± 0.5
5.5 ± 0.5
7.7 ± 0.5

Table 12.9

RF voltages along the initial RF signal path of the UHF radio (H5 and H6 bands)

Power level (W)

Frequency (MHz)
H5
band

H6
band

RF voltages (V)
Synthesizer
output

Buffer
output

Exciter
output

Driver
output

400
435
470

450
490
530

0.2 ± 0.1
0.2 ± 0.1
0.2 ± 0.1

0.3 ± 0.1
0.3 ± 0.1
0.4 ± 0.1

4.5 ± 0.5
4.6 ± 0.5
3.9 ± 0.5

2.3 ± 0.5
1.5 ± 0.5
0.8 ± 0.5

400
435
470

450
490
530

0.2 ± 0.1
0.2 ± 0.1
0.2 ± 0.1

0.3 ± 0.1
0.4 ± 0.1
0.4 ± 0.1

4.6 ± 0.5
4.6 ± 0.5
3.6 ± 0.5

3.6 ± 0.5
2.6 ± 0.5
1.2 ± 0.5

400
435
470

450
490
530

0.2 ± 0.1
0.2 ± 0.1
0.2 ± 0.1

0.2 ± 0.1
0.3 ± 0.1
0.3 ± 0.1

3.9 ± 0.5
4.0 ± 0.5
3.4 ± 0.5

4.5 ± 0.5
3.9 ± 0.5
1.7 ± 0.5

400
435
470

450
490
530

0.2 ± 0.1
0.1 ± 0.1
0.1 ± 0.1

0.2 ± 0.1
0.2 ± 0.1
0.2 ± 0.1

3.8 ± 0.5
3.6 ± 0.5
3.0 ± 0.5

4.6 ± 0.5
4.5 ± 0.5
1.8 ± 0.5

400
435
470

450
490
530

0.2 ± 0.1
0.2 ± 0.1
0.2 ± 0.1

0.3 ± 0.1
0.3 ± 0.1
0.3 ± 0.1

4.2 ± 0.5
3.6 ± 0.5
3.2 ± 0.5

8.6 ± 0.5
8.2 ± 0.5
2.5 ± 0.5

Transmitter Fault Finding (25W Radios)

357

Task 26 —
Output of Buffer in
Exciter Circuit

Task 27 —
Output of Exciter

358

If the synthesizer output is correct, check the output at C313 of the buffer
amplifier in the exciter circuit.
1.

If not already done, remove the PAD TOP can.

Enter the CCTM command 326 x, where x defines the power level
selected in Task 25.

Enter the CCTM command 101 x x 0, where x is the frequency
selected in Task 25.

Enter the CCTM command 33 to place the radio in transmit mode.

Measure the RF voltage after C313 (see Figure 12.15). (Use an
RFP5401A RF probe or the equivalent.) The required voltage
should be as given in Table 12.8 (B1 band) or Table 12.9 (H5, H6).

Enter the CCTM command 32 to place the radio in receive mode.

If the voltage measured above is correct, go to Task 27. If it is not, go
to Step 8.

Check the components around Q300 (see Figure 12.15).

Repair any fault revealed by the above checks. Replace Q300
(see Figure 12.15) if none of the other components is faulty.

10.

Confirm the removal of the fault and go to “Final Tasks” on
page 147. If the repair failed, replace the main-board assembly and go
to “Final Tasks” on page 147.

If the output of the buffer amplifier is correct, check that of the exciter at
C301.
1.

With the radio still in transmit mode, measure the RF voltage after
C301 (see Figure 12.15). (Use an RFP5401A RF probe or the
equivalent.) The required voltage should be as given in Table 12.8
(B1 band) or Table 12.9 (H5, H6).

If the voltage is correct, go to Task 28. If it is not, go to Step 3.

Enter the CCTM command 32 to place the radio in receive mode.

Check the components between C313 and Q303, and between
Q303 and R308 (see Figure 12.15).

Repair any fault revealed by the above checks. Replace Q303
(see Figure 12.15) if none of the other components is faulty.

Confirm the removal of the fault and go to “Final Tasks” on
page 147. If the repair failed, replace the main-board assembly and go
to “Final Tasks” on page 147.

Transmitter Fault Finding (25W Radios)

Task 28 —
Output of PA Driver

With the radio still in transmit mode, measure the RF voltage at the
drain of Q306 (B1) or after C317 and C389 (H5, H6)
(see Figure 12.15). (Use an RFP5401A RF probe or the equivalent.) The required voltage should be as given in Table 12.8 (B1) or
Table 12.9 (H5, H6).

Enter the CCTM command 32 to place the radio in receive mode.

If the voltage measured above is correct, go to Step 7. If it is not, go
to Step 4.

Check the components between C301 and Q306
(see Figure 12.15).

If the above checks reveal a fault, go to Step 6. If they do not, go to
Task 12 in “Biasing of PA Driver and PAs” on page 335.

Repair the fault. Confirm the removal of the fault and go to “Final
Tasks” on page 147. If the repair failed, replace the main-board
assembly and go to “Final Tasks” on page 147.

If not already done, remove the PAF TOP can.

Enter the CCTM command 326 5 to set the power level to the
maximum, and then the command 33 to place the radio in transmit
mode.

Measure the RF voltage at the gates of the PAs Q309 and Q310
(see Figure 12.16).

10.

Enter the CCTM command 32 to place the radio in receive mode.

11.

If an RF voltage is present, there is no fault in the initial RF signal
path; go to Task 29. If there is no RF voltage, go to Step 12.

12.

Check the components of the interstage matching circuitry between
the PA driver Q306 and the gates of the PAs Q309 and Q310
(see Figure 12.16).

13.

Transmitter Fault Finding (25W Radios)

359

Figure 12.16 Components of the interstage matching circuitry between the PA driver Q306 and the
PAs Q309 and Q310

B1 BAND
PAF TOP CAN

PAD TOP CAN

H5, H6 BANDS

360

Transmitter Fault Finding (25W Radios)

Task 29 —
Check Power at
Directional Coupler

If, as determined in Task 25 to Task 28, there is no fault in the initial RF
signal path, investigate the final signal path. This part of the circuitry may
also require investigation following certain checks in “Transmitter RF
Power”. Begin by checking the directional coupler as follows:
1.

If not already done, remove the DIRC TOP can.

Remove the coupling capacitors C348, C349, C350
(see Figure 12.17).

Solder one terminal of an 82pF (H5, H6 bands) or 680pF (B1) test
capacitor to the PCB at the point shown in Figure 12.17. Mount the
capacitor vertically. Use a test capacitor of the type GRM111, DLI
C17, Murata 1210, or the equivalent.

Solder a 50Ω test lead to the PCB: Solder the outer sheath to the test
pad shown in Figure 12.17, and solder the central wire to the other
terminal of the test capacitor.

Connect the test lead to the test set.

Enter the CCTM command 326 5 to set the transmitter power level
to the maximum.

Enter the CCTM command 101 x x 0, where x is the lowest
frequency (in hertz) for maximum power, as given in Table 12.8
(B1 band) or Table 12.9 (H5, H6).

Enter the CCTM command 33 to place the radio in transmit mode.

Measure the RF output power. This should exceed 35 W.
RF output power: more than 35W

10.

Enter the CCTM command 32 to place the radio in receive mode.

11.

Enter the CCTM command 101 x x 0, where x is the highest
frequency (in hertz) for maximum power, as given in Table 12.8
(B1 band) or Table 12.9 (H5, H6).

12.

Repeat Step 8 to Step 10.

13.

If the power measured in both the above cases exceeds 35W, go to
Step 14. If it does not, go to Task 30.

14.

Remove the test lead and test capacitor, resolder the coupling
capacitors in position, and go to Task 31.

Transmitter Fault Finding (25W Radios)

361

Figure 12.17 Circuitry under the DIRC TOP can, and the points for attaching the test lead and test
capacitor
B1 band

H5/H6 bands

Mounting point
for test capacitor

Test pad
Test pad

362

Transmitter Fault Finding (25W Radios)

Task 30 —
Repair Circuitry

If the RF output power measured in Task 29 is low, there is a fault in the
circuit between the common drain of the PAs and the test capacitor.
1.

If not already done, remove the PAF TOP can.

Check for faulty, shorted or misplaced components in the circuit
between the test capacitor and the common drain of Q309 and Q310
(see Figure 12.6 to Figure 12.7).

Repair any fault revealed by the above checks and go to Step 5. If no
fault could be found, go to Step 4.

Remove the test lead and test capacitor, resolder the coupling
capacitors C348, C349 and C350 in position (see Figure 12.17),
and go to Task 25.

With the test lead still connected to the test set, enter the CCTM
command 326 5 to set the transmitter power level to the maximum.

Enter the CCTM command 101 x x 0, where x is the lowest
frequency (in hertz) for maximum power, as given in Table 12.8
(B1 band) or Table 12.9 (H5, H6).

Enter the CCTM command 33 to place the radio in transmit mode.

Measure the RF output power. This should exceed 35 W.
RF output power: more than 35W

Enter the CCTM command 32 to place the radio in receive mode.

10.

Enter the CCTM command 101 x x 0, where x is the highest
frequency (in hertz) for maximum power, as given in Table 12.8
(B1 band) or Table 12.9 (H5, H6).

11.

Repeat Steps Step 7 to Step 9.

12.

Remove the test lead and test capacitor, and resolder the coupling
capacitors C348, C349 and C350 in position (see Figure 12.17).

13.

Transmitter Fault Finding (25W Radios)

363

Task 31 —
Check PIN Switch

Remove the PIN TOP can.

Remove the three blocking capacitors C361, C362 and C363
(see Figure 12.18).

Solder one terminal of a 22pF test capacitor to the PCB at the point
shown in Figure 12.18. Mount the capacitor vertically. Use a test
capacitor of the type GRM111, DLI C17, Murata 1210, or the
equivalent.

Solder a 50Ω test lead to the PCB. Solder the outer sheath to the test
pad shown in Figure 12.18, and solder the central wire to the other
terminal of the test capacitor.

Connect the test lead to the test set.

Enter the CCTM command 326 5 to set the transmitter power level
to the maximum.

Enter the CCTM command 101 x x 0, where x is the lowest
frequency (in hertz) for maximum power, as given in Table 12.8
(B1 band) or Table 12.9 (H5, H6).

Enter the CCTM command 33 to place the radio in transmit mode.

Measure the RF output power. This should exceed 35W.
RF output power: more than 35W

364

10.

Enter the CCTM command 32 to place the radio in receive mode.

11.

Enter the CCTM command 101 x x 0, where x is the highest
frequency (in hertz) for maximum power, as given in Table 12.8
(B1 band) or Table 12.9 (H5, H6).

12.

Repeat Step 8 to Step 10.

13.

If the power in both the above cases exceeds 35 W, go to Step 14. If it
does not, the circuitry of the PIN switch is suspect; go to Task 32.

14.

Remove the test lead and test capacitor, resolder the blocking
capacitors in position, and go to Task 33.

Transmitter Fault Finding (25W Radios)

Figure 12.18 Circuitry under the PIN TOP can, and points for attaching the test lead and test capacitor
B1 band
Test pad

H5/H6 bands
Test pad

Mounting point
for test capacitor

Transmitter Fault Finding (25W Radios)

365

Task 32 —
Repair PIN switch

If the RF power at the PIN switch is low, the switch is not drawing the
expected current or the diode is faulty. Check the circuit as follows:
1.

Perform a diode check of D307 (see Figure 12.18). If it is not faulty,
go to Step 2. If it is, replace D307 and go to Step 3.

Check the +9V0_TX supply to the PIN switch via the following
resistors on the bottom-side of the PCB (see Figure 12.19):
■

B1 band: R3080, R389 and R390

■

H5, H6 bands: R3000 and R389

If any resistor is faulty, replace the resistor as well as D307. (A faulty
resistor is likely to have resulted in damage to D307.)
3.

With the test lead still connected to the test set, enter the CCTM
command 326 5 to set the transmitter power level to the maximum.

Enter the CCTM command 101 x x 0, where x is the lowest
frequency (in hertz) for maximum power, as given in Table 12.8
(B1 band) or Table 12.9 (H5, H6).

Enter the CCTM command 33 to place the radio in transmit mode.

Again measure the RF output power. This should exceed 35W.
RF output power: more than 35W

366

Enter the CCTM command 32 to place the radio in receive mode.

Enter the CCTM command 101 x x 0, where x is the highest
frequency (in hertz) for maximum power, as given in Table 12.8
(B1 band) or Table 12.9 (H5, H6).

Repeat Step 5 to Step 7.

10.

Remove the test lead and test capacitor, and resolder the blocking
capacitors C361, C362 and C363 (see Figure 12.18) in position.

11.

If the power in both the above cases is now correct, the fault has been
rectified; go to “Final Tasks” on page 147. If it is not, the repair
failed: replace the main-board assembly and go to “Final Tasks” on
page 147.

Transmitter Fault Finding (25W Radios)

Figure 12.19 Components of concern on the bottom-side of the main board

COPPER PLATE

VCO BOT CAN

NB BOT CAN

B1 BAND

COPPER PLATE

VCO BOT CAN

H5, H6 BANDS

Transmitter Fault Finding (25W Radios)

367

Figure 12.20 Circuitry under the LPF TOP can (top side)
B1 band

368

H5/H6 bands

Transmitter Fault Finding (25W Radios)

Task 33 —
Check Components
of LPF

If there are no faults in the final RF signal path up to and including the PIN
switch, then the fault should lie in the LPF. Check the LPF as follows:
1.

Remove the LPF TOP can.

Connect the RF connector to the test set.

Check the capacitors and inductors of the LPF between the PIN
switch and the RF connector. See Figure 12.20. Check for shorts,
open circuits, and faulty components. Repair any fault.

Enter the CCTM command 326 5 to set the transmitter power level
to the maximum.

Enter the CCTM command 101 x x 0, where x is the lowest
frequency (in hertz) for maximum power, as given in Table 12.8
(B1 band) or Table 12.9 (H5, H6).

Enter the CCTM command 33 to place the radio in transmit mode.

Measure the RF output power. This should exceed 35W.
RF output power: more than 35W

Enter the CCTM command 32 to place the radio in receive mode.

Enter the CCTM command 101 x x 0, where x is the highest
frequency (in hertz) for maximum power, as given in Table 12.8
(B1 band) or Table 12.9 (H5, H6).

10.

Repeat Steps Step 6 to Step 8.

11.

If the power in both the above cases exceeds 35 W, the fault has been
rectified; go to “Final Tasks” on page 147. If it does not, the repair
failed; replace the main-board assembly and go to “Final Tasks” on
page 147.

Transmitter Fault Finding (25W Radios)

369

370

Transmitter Fault Finding (25W Radios)

CODEC and Audio Fault Finding

Fault Conditions

This section covers the diagnosis of faults in the CODEC and audio
circuitry. There are five conditions that indicate a possible fault in the
circuitry:
■

no speaker audio or speaker audio is distorted

■

no speaker audio at auxiliary connector

■

receiver does not operate

■

no transmit modulation or modulation is distorted

■

no transmit modulation despite modulation at auxiliary connector

In the first case regarding the speaker audio, the green STATUS LED will be
operating correctly and all unmute criteria will be satisfied. In the second
case the receiver will be operating normally. In the third case the assumption
is that the receiver and power-supply circuitry were checked and no faults
were found. In the fourth case regarding the transmit modulation, the radio
will be transmitting the correct amount of RF power. In the fifth case the
transmitter will be operating normally.
Fault-Diagnosis
Procedures

The procedures for diagnosing the above faults are given below in the
following sections. In each case, however, first carry out the tasks of “Power
Supplies” on page 372. Also note that the conditions concerning the
auxiliary connector can both occur at the same time. In this case carry out
both “No Speaker Audio at Auxiliary Connector” on page 382 and “Faulty
Modulation Using Auxiliary Connector” on page 394.

CCTM commands

The CCTM commands required in this section are listed in Table 13.1.
Full details of the commands are given in “Computer-Controlled Test
Mode (CCTM)” on page 112.

Table 13.1
Command

CCTM commands required for the diagnosis of faults in the CODEC and audio circuitry
Description

21
32
33

Unmute received audio
Set radio in receive mode
Set radio in transmit mode

110 x
323 x y
324 x y
400 x

Set level x (in range 0 to 255) of audio volume
Generate audio tone AUD TAP IN at tap point x of tap type y
Output audio signal at tap point x of tap type y to AUD TAP OUT
Select channel with channel number x

CODEC and Audio Fault Finding

371

13.1

Power Supplies

Introduction

First check that a power supply is not the cause of the fault. Of these
supplies, the 3.3V DC supply (+3V3) will already have been checked in
“Power Supply Fault Finding” on page 153. The remaining supplies that
need to be checked are:
■

Task 1: 9V DC supply from 9V regulator (+9V0)

■

Task 2: 3V DC supply from 3V regulator (+3V0 AN)

■

Task 3: 2.5V DC supply from 2.5V regulator (+2V5 CDC)

Two other supplies used in the CODEC and audio circuitry are a 1.8V DC
supply (+1V8) from the digital board and the 13.8V DC supply (+13V8 BATT)
from the power connector. Faults in these supplies are dealt with elsewhere.
Task 1 —
9V Power Supply

First check the 9V DC supply (+9V0), which is required by IC201.
1.

Remove the main-board assembly from the chassis.

Remove the CDC BOT can.

Measure the voltage +9V0 at pin 4 of IC201 (see Figure 13.1).
pin 4 of IC201: 9.0 ± 0.3V DC

Task 2 —
3V Power Supply

If the voltage is correct, go to Task 2. If it is not, go to Step 5.

The fault will be at IC201 (see Figure 13.1), since any fault with the
9V regulator in the PSU module will already have been rectified.
Therefore, check the soldering of IC201. Repair any fault.

Confirm the removal of the fault and go to “Final Tasks” on
page 147. If the repair failed or the fault could not be found, replace
the main-board assembly and go to “Final Tasks” on page 147.

If the 9V supply is correct, check the 3V DC supply (+3V0 AN) next.
1.

Measure the voltage +3V0 AN at the TP601 test point
(see Figure 13.1).
TP601 test point: 2.9 ± 0.3V DC

372

If the voltage is correct, go to Task 3. If it is not, go to Step 3.

The 3V regulator IC603 is suspect (see Figure 13.1). Check the
regulator as described in Task 3 of “Power Supply Fault Finding” on
page 158.

CODEC and Audio Fault Finding

Figure 13.1

Power-supply circuitry for the CODEC and audio circuitry under the CDC BOT can

LO2 BOT CAN

CAN FOR
DIGITAL
BOARD

CODEC and Audio Fault Finding

373

Task 3 —
2.5V Power Supply

If the 9V and 3V supplies are correct, the remaining power supply to check
is the 2.5V DC supply (+2V5 CDC).
1.

Measure the voltage +2V5 CDC at pin 5 of IC604 (see Figure 13.1).
pin 5 of IC604: 2.5 ± 0.3V DC

If the voltage is correct, go to Step 4. If it is not, go to Step 3.

The 2.5V regulator IC604 is suspect (see Figure 13.1). Check the
regulator as described in Task 3 of “Power Supply Fault Finding” on
page 158.

Proceed to the section relevant to the fault exhibited:
■

“Faulty Speaker Audio” (distorted or no speaker audio)

■

“No Speaker Audio at Auxiliary Connector” (no speaker audio at
auxiliary connector)

■

“Faulty Receiver” (receiver does not operate)

■

“Faulty Modulation” (distorted or no transmit modulation)

■

“Faulty Modulation Using Auxiliary Connector” (modulation at
auxiliary connector only)

Further details are given in the introduction to the section.

374

CODEC and Audio Fault Finding

13.2

Faulty Speaker Audio

Introduction

This section covers the case where the green STATUS LED is operating
correctly and all unmute criteria are satisfied, but there is either no speaker
audio or the speaker audio is distorted. There are four tasks:
■

Task 4: check audio power amplifier

■

Task 5: check speaker outputs

■

Task 6: check ITF VOL WIP DC input signal

■

Task 7: check ITF RX BEEP IN input signal

The next section deals with the case where there is no speaker audio at the
auxiliary connector.
Figure 13.2

Circuitry in the vicinity of IC202 (top side)

CODEC and Audio Fault Finding

375

Task 4 —
Check Audio
Power Amplifier

If there is no fault with the power supplies, check the inputs to the audio PA
as follows. This check is only applicable, however, if the output of the voiceband CODEC is correct and the signal level varies as the volume is varied.
1.

Use the programming application to find the frequency selected for
channel 1.

In user mode apply an on-channel RF signal of –47dBm with 60%,
1kHz deviation. The channel must not have signaling enabled.
Set the volume to maximum.

Use an oscilloscope probe to check the output of the voice-band
CODEC at the TP200 test point (see Figure 13.2). The signal
should be:
TP200 test point: sine wave of 100mVpp with 0.6V DC offset

If the above signal is correct, go to Step 5. If it is not, go to Task 7.

Vary the volume control. This should cause the signal level at the
TP200 test point (see Figure 13.2) to vary. If it does, go to Step 6.
If it does not, go to Task 6.

Check the voltage at pin 11 of IC202 (see Figure 13.2):
pin 11 of IC202: at least 8V DC

If the voltage is correct, go to Step 9. If it is not, check for and repair
any faults in the level-translation circuits incorporating Q200 and
Q201 (see Figure 13.2).

Confirm the removal of the fault and go to “Final Tasks” on
page 147. If the repair failed, replace the main-board assembly and go
to “Final Tasks” on page 147.

Check the digital signals DIG AUD PA EN1 at R200 and DIG AUD PA EN2 at
R202 (see Figure 13.2):
R200 (DIG AUD PA EN1): 3.3V DC
R202 (DIG AUD PA EN2): 0.0V DC

10.

376

If the signals are correct, go to Task 5. If they are not, check the
programming and test set-up; otherwise the digital board is faulty;
replace the main-board assembly and go to “Final Tasks” on
page 147.

CODEC and Audio Fault Finding

Task 5 —
Check Speaker
Outputs

If the inputs to the audio PA are not faulty, check the speaker outputs from
the PA.
1.

Check the positive and negative speaker outputs AUD ITF SPK+ and AUD
ITF SPK– at pins 3 and 8 respectively of IC202 (see Figure 13.2):
pin 3 of IC202 (AUD ITF SPK+): approximately half-rail bias
pin 8 of IC202 (AUD ITF SPK–): approximately half-rail bias

If the speaker outputs are correct, go to Step 5. If they are not, go to
Step 3.

Check for and repair any soldering faults around IC202
(see Figure 13.2), or else replace IC202.

Confirm the removal of the fault and go to “Final Tasks” on
page 147. If the repair failed, replace the main-board assembly and go
to “Final Tasks” on page 147.

With the volume at maximum, check each speaker output at pins 3
and 8 of IC202 (see Figure 13.2):
pin 3 of IC202 (AUD ITF SPK+): approximately 9.5Vpp AC
pin 8 of IC202 (AUD ITF SPK–): approximately 9.5Vpp AC

If the speaker outputs are correct, the fault is unknown (it could be
intermittent); replace the main-board assembly and go to “Final
Tasks” on page 147. If there is no AC, go to Step 7.

Check that C204 and R214 (see Figure 13.2) are not faulty and are
correctly soldered. Repair any fault.

CODEC and Audio Fault Finding

377

Circuitry under the CDC TOP can, and adjacent interface circuitry

Junction of
R708 and C706

Junction of
R234 and R235

Figure 13.3

378

CODEC and Audio Fault Finding

Task 6 —
Check ITF VOL WIP DC
Input Signal

If the output of the voice-band CODEC is correct, but the signal level does
not vary as the volume control is varied, check the ITF VOL WIP DC signal.
1.

Check the voltage on the VOL WIP DC line at the junction of R708 and
C706 (see Figure 13.3). As the volume varies, the voltage should
vary as follows.
junction of R708 and C706: 0.0 to 1.2V as volume varies

If the voltage varies as expected, go to Step 5. If it does not, go to
Step 3.

Check the control-head connector SK100. Repair or replace the
connector if necessary.

Remove the CDC TOP can.

Check the voltage at the junction of R234 and R235
(see Figure 13.3). As the volume varies, the voltage should vary as
follows.
junction of R234 and R235: 0.0 to 0.6V as volume varies

If the voltage varies as expected, CODEC 1 (IC204) is suspect;
replace the main-board assembly and go to “Final Tasks” on
page 147. If it does not, go to Step 8.

Check for continuity across R234, and check that R235 is properly
soldered (see Figure 13.3). Repair any fault.

CODEC and Audio Fault Finding

379

Figure 13.4

Circuitry under the CDC BOT can

CDC AUD TAP OUT

JUNCTION OF R218 AND IC204

LO2 BOT CAN

CAN FOR
DIGITAL
BOARD

380

CODEC and Audio Fault Finding

Task 7 —
Check ITF RX BEEP IN
Input Signal

If the output of the voice-band CODEC is not correct, check the
ITF RX BEEP IN signal.
1.

If not already done, remove the CDC BOT can.

Check the signal at the junction of R218 and IC204
(see Figure 13.4). The signal should be:
junction of R218 and IC204: sine wave about 1Vpp with 1.2V DC offset

If the signal is correct, go to Step 4. If it is not, either CODEC 1
(IC204) or the digital board is faulty; replace the main-board
assembly and go to “Final Tasks” on page 147.

Check for continuity between the TP200 test point and IC204 via
R214, R215 (see Figure 13.2) and R218 (see Figure 13.4).
Repair any fault; if necessary, replace R214, R215 or R218.

CODEC and Audio Fault Finding

381

Figure 13.5

Circuitry in the vicinity of the internal-options connector SK102 (top side)

Internal-options
connector

13.3

No Speaker Audio at Auxiliary Connector

Introduction

This section covers the case where the receiver operates normally but there
is no speaker audio at the auxiliary connector. In other words, there is no
signal at pin 13 (AUD TAP OUT) of the connector. The fault-diagnosis
procedure comprises two tasks:
■

Task 8: check signal from CODEC

■

Task 9: check LPF and buffer amplifier in CODEC circuitry

These tasks need to be followed by those of “Faulty Modulation Using
Auxiliary Connector” on page 394 if there is also a fault with the transmit
modulation using the auxiliary connector.

382

CODEC and Audio Fault Finding

Task 8 —
Check Signal
from CODEC

First generate an appropriate audio test signal and check whether the signal
is present at the output of the CODEC circuitry.
1.

Enter the CCTM command 400 x, where x is a valid channel number.
(A suitable channel will depend on the programming of the radio.)

Enter the CCTM command 21 to force unmuting of the received
audio signal.

Enter the CCTM command 110 128 to set the audio level at its
midpoint.

At the test set apply 60%, 1kHz modulation to the RF signal. Reduce
the volume to a minimum.

Enter the CCTM command 324 r5.

Check that the received signal is present at pin 2 (AUD TAP OUT) of the
internal-options connector SK102 (see Figure 13.5) (alternatively,
the measurement point for CDC AUD TAP OUT shown in Figure 13.4).
The signal should be:
pin 2 of internal-options connector: received signal with 2.4V DC offset

If the above signal is correct, go to Step 8. If it is not, go to Task 9.

Check the components in the path from pin 13 of the auxiliary
connector SK101 to the CODEC and audio circuitry. These are
C719 and L708 (see Figure 13.6) and the link R747
(see Figure 13.5). Also check the auxiliary connector itself. Repair
any fault.

Confirm the removal of the fault and go to Step 10. If the repair failed
or the fault could not be found, replace the main-board assembly and
go to “Final Tasks” on page 147.

10.

If there is also a fault with the transmit modulation, notwithstanding
modulation at the auxiliary connector, go to Task 15 of “Faulty
Modulation Using Auxiliary Connector” on page 394. If there is no
other fault, go to “Final Tasks” on page 147.

CODEC and Audio Fault Finding

383

Figure 13.6

Circuitry in the vicinity of the auxiliary connector (bottom side)

AUXILIARY CONNECTOR
SK101

384

CODEC and Audio Fault Finding

Task 9 —
Check LPF and
Buffer Amplifier

If there is no test signal at the internal-options connector, then either
CODEC 1 is faulty or there is a fault in the LPF or buffer amplifier.
1.

Remove the CDC BOT can.

Check the signal at the junction between R224 and IC204
(see Figure 13.7). This should be:
junction of R224 and IC204: 0.7Vpp with 2.4V DC offset

If the above signal is correct, go to Step 4. If it is not, CODEC 1
(IC204) is faulty; replace the main-board assembly and go to “Final
Tasks” on page 147.

Check the voltage at pin 1 of IC201 (see Figure 13.7).
pin 1 of IC201: 1.2V

If the voltage is correct, go to Step 6. If it is not, check the LPF circuit
based on IC201 (pins 1 to 3) (see Figure 13.7). Repair any fault and
conclude with Step 9.

Check the voltage at pin 7 of IC201 (see Figure 13.7).
pin 7 of IC201: 2.4V

If the voltage is correct, go to Step 8. If it is not, check the buffer
amplifier based on IC201 (pins 5 to 7) (see Figure 13.7). Repair any
fault and conclude with Step 9.

Check R207 and R208 (see Figure 13.7). Repair any fault and
conclude with Step 9.

Confirm the removal of the fault and go to Step 10. If the repair failed
or the fault could not be found, replace the main-board assembly and
go to “Final Tasks” on page 147.

10.

If there is also a fault with the transmit modulation, notwithstanding
modulation at the auxiliary connector, go to “Faulty Modulation
Using Auxiliary Connector” on page 394. If there is no other fault,
go to “Final Tasks” on page 147.

CODEC and Audio Fault Finding

385

Figure 13.7

Circuitry under the CDC BOT can
CAN FOR DIGITAL BOARD

LO2 BOT CAN

JUNCTION
OF R224
AND IC204

386

CODEC and Audio Fault Finding

13.4

Faulty Receiver

Introduction

This section covers the case where the receiver does not operate, although
there is no apparent fault in the receiver circuit itself. There are two tasks:
■

Task 10: check level shifter

■

Task 11: check QN test point

The latter check will isolate the module at fault if the level shifter is not the
cause of the problem.
Task 10 —
Check Level Shifter

Check the operation of the base-band CODEC and receiver AGC as
described below. This concerns the level-shifter circuit. It is assumed that the
receiver and power-supply circuitry were checked and no faults were found.
1.

If not already done, remove the CDC BOT can.

With no RF signal applied, check the voltage at pin 14 of IC201
(see Figure 13.7):
pin 14 of IC201: more than 2.5V DC

If the above voltage is correct, go to Task 11. If it is not, go to Step 4.

Check the voltage at pin 12 of IC201 (see Figure 13.7):
pin 12 of IC201: more than 1V DC

If the above voltage is correct, go to Step 8. If it is not, go to Step 6.

Check for and repair any shorts to ground at the junction of R238
and pin 12 of IC201 (see Figure 13.7).

Check the circuitry (R238, R239, R240) around pins 12, 13 and 14
of IC201 (see Figure 13.7). Repair any fault.

CODEC and Audio Fault Finding

387

Figure 13.8

Circuitry in the vicinity of the CDC TOP can

B1 band

Junction of
C708 and C732

H5/H6 bands

Junction of
C708 and C732

388

CODEC and Audio Fault Finding

Task 11 —
Check QN Test Point

If the level shifter is not faulty, check the signal at the QN test point. This will
ascertain whether the digital board, CODEC 1, or the receiver is at fault.
1.

Use the programming application to find the frequency selected for
channel 1.

Apply a strong on-channel signal.

Check that a sine wave is present at the QN test point (there is access
through a hole in the IF TOP can — see Figure 13.8).
QN test point: sine wave

If there is a sine wave present, go to Step 5. If there is not, go to
“Receiver Fault Finding” on page 227.

Either the digital board or CODEC 1 (IC204) is faulty; replace the
main-board assembly and go to “Final Tasks” on page 147.

CODEC and Audio Fault Finding

389

13.5

Faulty Modulation

Introduction

This section covers the case where the radio transmits the correct amount of
RF power, but there is either no modulation or the modulation is distorted.
There are three tasks:
■

Task 12: initial checks

■

Task 13: check 2.3V DC supply

■

Task 14: check bias network

The initial checks will determine whether the frequency synthesizer, the
2.3V supply, or the bias network is at fault.
Task 12 —
Initial Checks

Carry out the following checks to isolate the part of the circuitry that is
faulty.
1.

Apply a 1kHz audio signal of 20 mVpp at the microphone input on
the control head.

Enter the CCTM command 33 to place the radio in transmit mode.
(The frequency is that of channel 1.)

Check that the 1kHz signal appears at the TP503 test point
(see Figure 13.8).
TP503 test point: 1kHz signal

Enter the CCTM command 32 to place the radio in receive mode.

If the 1kHz signal is present, go to “Frequency Synthesizer Fault
Finding” on page 169. If it is not, go to Step 6.

With no microphone connected, check the voltage at the junction of
C708 and C732 (CH MIC AUD) (see Figure 13.8):
junction of C708 and C732: approximately 3V

390

If the above voltage is correct, go to Task 14; the bias network is
suspect. If it is not, go to Task 13; the 2.3V supply is suspect.

CODEC and Audio Fault Finding

Figure 13.9

Circuitry in under the CDC BOT can

LO2 BOT CAN

CAN FOR
DIGITAL
BOARD

CODEC and Audio Fault Finding

391

Task 13 —
Check 2.3V Supply

If the CH MIC AUD signal is not as expected, the 2.3V supply needs to be
checked.
1.

If not already done, remove the CDC BOT can.

Check the voltage across C202 (see Figure 13.9):
voltage across C202: 3V

Task 14 —
Check Bias Network

If the above voltage is correct, go to Task 14. If it is not, go to Step 4.

Check the soldering of R209, and check for shorts to ground at C202
(see Figure 13.9). Repair any fault.

If the signal at the TP503 test point is incorrect, but the other checks in the
above tasks reveal no fault, check the bias network.
1.

Remove the CDC TOP can.

Check the voltage at the junction of R229 and R232
(see Figure 13.10):
junction of R229 and R232: 1.5V DC

392

If the voltage is correct, go to Step 4. If it is not, go to Step 5.

CODEC 1 (IC204) is faulty; replace the main-board assembly and go
to “Final Tasks” on page 147.

Check the soldering of R229 and R232, and check for shorts across
R232 (see Figure 13.10). Repair any fault.

CODEC and Audio Fault Finding

Figure 13.10 Circuitry under the CDC TOP can

JUNCTION OF
R229 AND R232

ITF AUD TAP IN
JUNCTION OF R237 AND R241

CODEC and Audio Fault Finding

393

13.6

Faulty Modulation Using Auxiliary Connector

Introduction

This section covers the case where the transmitter operates normally but
there is no modulation (although there is modulation at the auxiliary
connector). There are two tasks:
■

Task 15: apply AUD TAP IN signal

■

Task 16: check CODEC 2 device

If there was also a fault with the speaker audio at the auxiliary connector, it
is assumed that this has now been rectified.
Task 15 —
Apply AUD TAP IN
Signal

First check the modulation and, if necessary, the DC offset.
1.

Enter the CCTM command 33 to place the radio in transmit mode.
(The frequency is that of channel 1.)

Check the modulation via the microphone input.

Enter the CCTM command 32 to place the radio in receive mode.

If the modulation is correct, go to Step 5. If it is not, go to Task 12
of “Faulty Modulation” on page 390.

Apply a 1kHz AC-coupled signal of 0.7Vpp at pin 7 (AUD TAP IN) of
the auxiliary connector (alternatively, as ITF AUD TAP IN at the junction
of R237 and R241 — see Figure 13.10).

Enter the CCTM command 323 t5.

Check the DC offset voltage at pin 7:
pin 7 of auxiliary connector: approximately 1.5V DC offset

394

If the above DC offset is correct, go to Step 9. If it is not, go to
Step 11.

Remove the CDC TOP can.

10.

Check for and repair any soldering faults around IC205, or else
replace IC205 (see Figure 13.10). Conclude with Step 12.

11.

Check for shorts at pin 7 of the auxiliary connector. If there are none,
go to Task 16. If there are, repair the fault and conclude with Step 12.

12.

Confirm the removal of the fault and go to “Final Tasks” on
page 147. If the repair failed, replace the main-board assembly and go
to “Final Tasks” on page 147.

CODEC and Audio Fault Finding

Task 16 —
Check CODEC 2
Device

If the DC offset measured in Task 15 is incorrect but there is no fault with
the auxiliary connector, check the CODEC 2 device.
1.

Remove the CDC TOP can.

Check the voltage at both ends of R241 (see Figure 13.10):
R241: 1.5V DC at both ends

If the voltages are correct, go to Step 4. If they are not, go to Step 6.

Check for and repair any soldering faults around IC205, or else
replace IC205 (see Figure 13.10).

Confirm the removal of the fault and go to “Final Tasks” on
page 147. If the repair failed, replace the main-board assembly and go
to “Final Tasks” on page 147.

Remove R241.

Check the voltage at pin 3 of IC205 (see Figure 13.10):
pin 3 of IC205: 1.5V DC

If the above voltage is correct, go to Step 9. If it is not, replace the
main-board assembly and go to “Final Tasks” on page 147.

Check for and repair any soldering faults around R241 and IC205
(see Figure 13.10).

10.

Confirm the removal of the fault and go to “Final Tasks” on
page 147. If the repair failed, replace the main-board assembly and go
to “Final Tasks” on page 147.

CODEC and Audio Fault Finding

395

396

CODEC and Audio Fault Finding

14
Overview

Fault Finding of Control Head
This section describes the fault finding of the control head for the following
faults:
■

power supply faulty (initial check)

■

LCD display faulty

■

LCD backlighting faulty

■

LCD contrast faulty

■

LCD heating faulty

■

function key LEDs or status LEDs faulty

■

keypad backlighting faulty

■

ON/OFF

■

function, scroll, or selection keys faulty

■

speaker faulty

■

volume control faulty

■

PTT faulty

key faulty

The faults can be detected by visual inspection (refer to “Visual Inspection”
on page 128) or using the CCTM commands in Table 14.1 on page 398.
General

The following applies for all fault finding procedures:
Important

Do not disconnect or connect the control head while
power is supplied to the radio.

■

To connect to ground use one of the screw bosses of the metal
spaceframe or the screw bosses of the radio body.

■

If the radio does not switch on when power is supplied, the radio may
be programmed to go into the status it was in when powered down.
Connect a known good control head, power up the radio, and change
the relevant setting in the programming application. Remember to
program the original setting before returning the radio to the customer.

■

For disassembly and re-assembly instructions, refer to “Disassembling
and Reassembling the Control Head” on page 135.

■

If the repair fails or no fault could be found, replace the control-head
board.

■

After completing the repair, carry out the tasks in “Final Tasks” on
page 147.

Fault Finding of Control Head

397

14.1

CCTM Commands
The following CCTM commands are used during the fault finding of the
control head:

Table 14.1

CCTM commands for fault finding of the control head

CCTM command

Entry at keyboard

Response on screen

1000 – All function key LEDs and status LEDs 1000 0 = off
sequentially switches the function key LEDs and 1000 1 = on
the status LEDs on and off

none

1001 – Individual function key LEDs and
status LEDs
switches individual LEDs on and off

1001 x y
none
where x is the LED number (0=F1,
1=F4, 2=yellow, 3=green, 4=red),
and y is the state (0=off, 1=on)

1002 – LED intensity
sets the LED intensity

1002 0 = off
1002 1 = low
1002 2 = medium
1002 3 = high

none

1003 – Keypad backlighting
Activate keypad backlighting at specified
intensity

1003 0 = off
1003 1 = low
1003 2 = medium
1003 3 = high

none

1004 – LCD backlighting
Activate LCD backlighting at specified intensity

1004 0 = off
1004 1 = low
1004 2 = medium
1004 3 = high

none

1005 – LCD contrast
sets the LCD contrast (16 levels)

1005 x
where x is the contrast level
(0 to 15)

none

1006 – LCD elements
switches all LCD elements on and off

1006 0 = off
1006 1 = on

none

1007 – LCD temperature sensor
Reads the LCD temperature sensor

1007

value between 00 (0)
and FF (255)

1008 – LCD heating
switches the LCD heating on and off

1008 0 = off
1008 1 = on

1009 – Key press
detects and notifies individual key press and
release events

1009 0 = off
1009 1 = on

serial output

1010 – Volume potentiometer
reads and notifies the volume potentiometer
setting

1010

value between 00 (0)
and FF (255)

1011 – Microphone
selects the microphone input source

1011 0 = microphone connector
1011 2 = covert microphone

none

398

Fault Finding of Control Head

The following CCTM commands are used during the fault finding of the
remote control-head kit:
Table 14.2

CCTM commands for fault finding of the remote control-head kit

CCTM command

Entry at keyboard

Response on screen

1012 – Remote kit
turns the audio amplifier on and off

1012 0 = off
1012 1 = on

none

1013 – Mute audio amplifier
mutes and unmutes the audio amplifier

1012 0 = mute
1012 1 =unmute

none

1014 – Digital potentiometer
reads the digital potentiometer

1014

value between 0 and
255

1017 – Audio amplifier gain
sets the audio amplifier gain (4 levels)

1017 x
where x is the gain (0 to 3)

none

Fault Finding of Control Head

399

14.2

Power Supply Faulty
A 3.3V regulator (U1) converts the switched 13.8V supply from the radio
body to 3.3V. A 1.5V regulator (U203) converts the 3.3V to 1.5V.
A power-sense module (U202) verifies the outputs of the voltage regulators
and—in the case of a fault—creates a power reset signal which is processed
by the FPGA. If the start-up of the control head fails, the radio body reduces
the switched 13.8V supply shortly after power is supplied.

2
IN
1
EN

OUT

L201

3V3

E202

3V3

R206

C14

C210

R205

D201

8
VCC
1
OUT
2
SYNC
4
6
COMP U1 VREF
3
INH
5
FB
GND
7
GND

E203

U203 RST 5

1V5
1V5

C202

C12

R18 C13

C206
R210

Q201

C201

R208

R16 D1
R17

ControlHead
Connector

C11

C207

J103

13V8
2

Circuit diagram of the power supply circuitry

C205

Figure 14.1

GND
3 6

FPGA

R202
MR
PWR WDT

K1 AA

PWR RESET

D203
K2 AA

C204

S201

3
1
MR
RST
6
7
PFI U202 PFO
8
2
WDI
WDI
GND
5

3V3

D203

R201

R203

R204
DNI

3V3

For all faults, check that the supply voltages are correct:
1.

Check the 3.3V supply voltage between E202 and C210.
E202/C210: 3.3V

If the signal is correct, continue with step 4.
If the signal is not correct, visually inspect the components E202,
D201, L201, R205, and R206 for open or shorted contacts.
Replace if necessary. Continue with step 2.
2.

Check the 13.8V supply voltage (9.7V to 17.2V) between pin 2 of
the control-head connector J103 and pin 8 of U1.
J103 pin 2: 13.8V (Vs =9.7V…17.2V)
U1 pin 8: 13.8V (Vs =9.7V…17.2V)

If the signal is correct, continue with step 3.
Note

400

A fault in the control head can cause the radio body to reduce the
switched 13.8V supply shortly after power is supplied. In this case,
the control head must be supplied directly through pin 2 of connector J103.

Fault Finding of Control Head

If the signal is not correct, check the 13.8V supply voltage from the
radio body. Return to step 1.
3.

Check the inhibit signal at pin 3 of U1.
U1 pin 3: high: >2.2V, low: < 0.7V
D1: Vs – 5.1V

If the signal is above 2.2V, visually inspect the components D1, R16,
R17, R208, and Q201 for open or shorted contacts. Replace if necessary. Return to step 1.
If the signal is low, replace U1. Return to step 1.
4.

Check the 1.5V supply voltage at pin 4 of U203.
U203 pin 4: 1.5V

If the signal is correct, continue with step 6.
If the signal is not correct, continue with step 5.
5.

Check E203 for continuity.
E203: 1.5V

If E203 is correct, continue with step 6
If E203 is faulty, replace E203 and return to step 4.
6.

U202 detects a possible power failure and generates an output signal
on pin 7. Check whether this signal is low.
U202 pin 4: 3.3V
U202 pin 7: 3.3V

If pin 4 measures 3.3V and pin 7 is low, replace U202.
If pin 4 measures 3.3V and pin 7 is high, replace U203.
Figure 14.2

PCB layout of the power supply circuitry

Junction of C210 and E202

top side

Fault Finding of Control Head

401

14.3

LCD Display Faulty
The LCD module is connected to the control-head board via the LCD
connector. The LCD module display is controlled by a serial data link to the
FPGA. A faulty LCD display can be caused by the following:
■

a loose or dirty LCD loom connection,

■

a faulty LCD, or

■

a fault on the control-head board

Note

Figure 14.3

This section only deals with the display of the LCD. For faults of
the LCD backlighting, refer to “LCD Backlighting Faulty” on
page 404.

Circuit diagram of the LCD circuitry
3V3
LCD BACKLIGHT CTRL

3V3

Q102

LCD HEATER CTRL

Q102

FPGA
LCD RESETN
LCD D/C
LCD SCLK
LCD DAT
LCD CEN

3V3

LCD RESETN
LCD D/C
LCD SCLK
LCD DAT
LCD CEN
LED

R7
R5
R8
R6

E108
HEATER

C101

C102
C103

U601

LCD Connector
1
2
3
4
5
6
7
8
9
10
11
12
13
14

J102

LCD RESETN
2

Note

If some of the LCD pixels are faulty (usually complete rows or
lines), send CCTM command 1006 1 to activate all LCD pixels.
If some of the LCD pixels are faulty, replace the LCD.

If the LCD display is faulty:
1.

402

Disconnect the LCD loom, visually inspect and clean the contacts,
and reconnect the LCD loom. Visually inspect connector J102 for
open or shorted contacts.

Fault Finding of Control Head

Check the 3.3V supply voltage at pin 2 of the LCD connector J102.
J102 pin 2: 3.3V

If the signal is not correct, refer to “Power Supply Faulty” on
page 400.
Tip

For a quick check of the LCD without having to disassemble the
control head, connect a good LCD to the control head, or disconnect the LCD loom and connect it to a good control head.

Replace the LCD. Take care not to scratch the soft polarizer material
on the top side of the LCD.

Use an oscilloscope to check the signals of pins 3 to 7 of connector
J102.
J102 pins 3 to 7:

The signals should be switching 0 to 3.3V in bursts of
0.125ms at approximately 1s intervals.

If any of the signals are missing or distorted, remove can E100 and
check for continuity between the FPGA and the LCD connector.
If necessary, replace the corresponding 100Ω resistor R4 to R8.
Figure 14.4

PCB layout of the LCD circuitry

top side

Fault Finding of Control Head

403

14.4

LCD Backlighting Faulty
The backlighting incorporated in the LCD module is controlled by a data
line from the FPGA, which switches a transistor on MOSFET Q102.
Note

The LCD backlighting has four brightness settings: off=GND,
on=3.3V, and two intermediate settings which are implemented
by pulse-width modulation.

For a circuit diagram and PCB layout, refer to Figure 14.3 on page 402 and
Figure 14.4 on page 403.
If the LCD backlighting is faulty:
1.

Make sure that LCD backlighting has been enabled in the programming application.

Check the 3.3V supply voltage at pin 1 (S1) of Q102.
Q102 pin 1 (S1): 3.3V

If the signal is correct, continue with step 3.
If the signal is not correct, refer to “Power Supply Faulty” on
page 400
3.

Send CCTM command 1004 3 to switch on LCD backlighting.

Check the signal at pin 2 (G1) of Q102.
Q102 pin 2 (G1): GND (with backlighting switched on)

If the signal is correct, continue with step 5.
If the signal is not correct, visually inspect pin 2 for open contact.
Otherwise the FPGA is faulty and the control-head board must be
replaced.
5.

Check the signal at pin 7 (DA1) of Q102.
Q102 pin 7 (D1A): 3.3V (with backlighting switched on)

If the signal is correct, continue with step 6.
If the signal is not correct, replace Q102.
6.

Visually inspect whether the contact of pin 8 of connector J102 is
open or shorted. Check the signal at pin 8 of connector J102.
J102 pin 8: 3.3V (with backlighting switched on)

If the signal is correct, replace the LCD.

404

Fault Finding of Control Head

14.5

LCD Heating Faulty
The heating incorporated in the LCD module is controlled by a data line
from the FPGA, which switches a transistor on MOSFET Q102.
A temperature signal from the LCD module is converted to a digital signal
by an analog/digital converter (U601) and processed by the FPGA.
Note

The temperature sensor signal is independent from the heating
and is also used to control the LCD contrast.

For a circuit diagram and PCB layout, refer to Figure 14.3 on page 402 and
Figure 14.4 on page 403.
If the LCD heating is faulty:
1.

Check the temperature sensor signal at pin 14 of J102.
J102 pin 14: 1.52V at 30°C, 1.58V at 25°C, 1.64V at 20°C, 1.69V at 15°C

If the signal is below 0.7V (low) or above 2.5V, (high), the LCD temperature sensor is faulty.
2.

Send CCTM command 1007 to read the temperature sensor value.
If the value does not correspond to the ambient temperature, U601
is faulty.

Check the 3.3V supply voltage at pin 3 (S2) of Q102.
Q102 pin 3 (S2): GND

If the signal is not correct, refer to “Power Supply Faulty” on
page 400.
4.

Check the signal at pin 4 (G2) of Q102.
Q102 pin 4 (G2): GND (with heating switched on)

If the signal is not correct, visually inspect pin 4 for open contact.
Otherwise the FPGA is faulty and the control-head board must be
replaced.
5.

Check the signal at pin 5 (DA2) of Q102.
Q102 pin 5 (D2A): 3.3V (with heating switched on)

If the signal is missing, replace Q102.
6.

Visually inspect pins 10 and 12 of connector J102 for open or shorted
contacts.

Check the signal at pins 10 and 12 of connector J102.
J102 pins 10 and 12: 3.3V (with heating switched on)

If the signal is not correct, replace the LCD.

Fault Finding of Control Head

405

14.6

Function Key LEDs or Status LEDs Faulty
The function key LEDs (F1 and F4) and the red, green and amber status
LEDs each are controlled by an FPGA signal and a transistor (Q604 to
Q608). The brightness level is controlled by two FPGA signals, resulting in
four intensity levels (off, low, medium and high).

Figure 14.5

Circuit diagram of the function key LEDs and status LEDs
3V3

3V3

R34

R35

F1 Key

IND BRIGHT1

R601

D613

Q604

3V3
3V3

F4 Key

D614

Q605

3V3

R36

Red

D615

Green

Q606

D616

Amber

Q607

D617

Q608

R602
IND BRIGHT2
R603

R604

R605

R609

R612

R616

FPGA
LED FUNC 1
LED FUNC 4
LED IND TX
LED IND RX
LED IND BUSY

LED Faulty

If one of the function key LEDs or status LEDs is faulty:
1.

Send CCTM command 1001 x 1 (where x is the LED number:
0=F1, 1=F4, 2=amber, 3=green, 4=red) to activate the relevant
LED.

Check the resistors R34, R35, and R36 in the paths of the green
LEDs.
R34: 0Ω
R35: 0Ω
R36: 0Ω

Measure the voltage at the point between the LED and the transistor.
D613/Q604 (F1 key LED):
D614/Q605 (F4 key LED):
D615/Q606 (red status LED):
D616/Q607 (green status LED):
D617/Q608 (amber status LED):

1.87V (on)
1.87V (on)
1.92V (on)
1.87V (on)
1.89V (on)

1.40V (off)
1.40V (off)
1.57V (off)
1.40V (off)
1.48V (off)

If the voltage is incorrect, replace the LED.
4.
LED Intensity Faulty

406

Replace the corresponding transistor.

If the intensity of the LEDs is faulty:
1.

Send CCTM command 1001 0 1 to activate the LED of the F1 key.

Send CCTM command 1002 3 to set the LED intensity level to high.

Fault Finding of Control Head

Check the resistors R601 and R602, and replace if necessary.
R601: 2.2kΩ
R602: 5.62kΩ

If the resistors are okay, the FPGA is faulty and the control-head
board must be replaced.
Figure 14.6

PCB layout of the function key LED and status LED circuitry

top side

top side
bottom side

bottom side

Fault Finding of Control Head

407

14.7

Keypad Backlighting Faulty
The keypad backlighting LEDs are controlled by two FPGA signals and two
transistors (Q2), resulting in four intensity levels (off, low, medium and
high). The keypad backlighting LEDs are arranged in two groups for the
main keypad and one group for the on/off keypad, each group consisting of
three LEDs.

Figure 14.7

Circuit diagram of the keypad backlighting circuitry
Main Keypad
3V3

KEY BRIGHT0

47K
10K

FPGA

13V8

3V3

R607

13V8

R30

R617

R614

D607

D609

D605

D610

D611

D606

D608

D612

Q603

Q609

Q610

R615

R618

R619

R611

KEY BRIGHT1

R613

One LED or
One Group of LEDs
Faulty

D618

Send CCTM command 1003 x (where x is the intensity: 0=off,
1=low, 2=medium, 3=high) to switch on keypad backlighting.

Check the 13.8V supply voltage of the relevant branch.

From top to bottom, check the resistor, the three LEDs, and the
transistor of the relevant branch for continuity.
R617: 4.7Ω
D607: 1.9V (on)
D609: 1.9V (on)
D611: 1.9V (on)
Q609: 1.9V (on)
R618: 56Ω

R614: 4.7Ω
D605: 1.9V (on)
D606: 1.9V (on)
D618: 1.9V (on)
Q610: 1.9V (on)
R619: 56Ω

If all LEDs are faulty or the intensity is faulty:
1.

408

On/Off
Keypad

If one LED or one group of three LEDs is faulty:

R30: 4.7Ω
D607: 1.9V (on)
D610: 1.9V (on)
D608: 1.9V (on)
Q603: 1.9V (on)
R615: 56Ω

All LEDs Faulty or
Intensity Faulty

13V8

Send CCTM command 1003 x (where x is the intensity: 0=off,
1=low, 2=medium, 3=high) to switch on keypad backlighting.

Fault Finding of Control Head

With the intensity set to high, check the signals at pins 2 (B1) and 5
(B2) of Q2.
Q2 pin 2 (B1): GND
Q2 pin 5 (B2): GND

If any of these signals are incorrect, the FPGA is faulty and the control-head board must be replaced.
3.

Check the signals at pins 6 (C1) and 3 (C2) of Q2. Check the signals
at pins 1 (E1) and 4 (E2) of Q2.
Q2 pin 6 (C1): 3.3V
Q2 pin 3 (C2): 3.3V
Q2 pin 1 (E1): 3.3V
Q2 pin 4 (E2): 3.3V

If any of these signals are incorrect, Q2 is faulty.
4.

Check the resistors R607, 611, and R613 for shorted or open
circuits.
R607: 3.3kΩ
R611: 2.2kΩ
R613: 1kΩ

Figure 14.8

PCB layout of the keypad backlighting circuitry

top side

top side
bottom side

Fault Finding of Control Head

409

14.8

On/Off Key Faulty
When battery power (13.8V) is applied to the radio, a press of the ON/OFF key
will create an active low signal (CH ON OFF) back to the radio body to initiate
the power-on or power-off sequence. This key-press will also be detected
by the FPGA of the control head through Q611 as an active high signal
(POWER ON OFF 3V3). For more information on the start-up process, refer to
“Software Architecture” on page 44.
Figure 14.9

Circuit diagram of the ON/OFF key
3V3

Control-Head
Connector

13V8

R628
R606

J103

POWER ON OFF 3V3

R626

CH ON OFF
9

R610

FPGA

Q611

R627

Power
On/Off

S610
2

If the ON/OFF key is faulty:
1.

Use isopropyl alcohol and a soft lens-cleaning cloth to clean the pads
S610 on the control-head board for the ON/OFF key.

Check the CH ON OFF signal level from the radio at pin 9 of the
control-head connector J103.
J103 pin 9: 13V

If the signal is approx. 13V, continue with step 5.
If near or at ground, continue with step 3.
3.

Visually inspect pin 9 of connector J103 for open or shorted contacts.

Verify the source of the signal to pin 9 of connector J103 from the
radio (without the control-head connector).

Visually inspect R610, R606, and R624 for short-circuit to adjacent
components. Replace if necessary. Return to step 2.

Visually inspect R610 for shorted or open circuits. Repair if
necessary. Retest switch.

Verify continuity between R610 and switch S610, and continuity
between switch S610 and ground.
If the continuity cannot be restored, replace the control-head board.

410

Fault Finding of Control Head

Figure 14.10 PCB layout of the power on/off key circuitry

top side

bottom side

Fault Finding of Control Head

411

14.9

Function, Scroll, or Selection Keys Faulty
The eight keys of the main keypad (function, scroll, and selection keys) are
connected to the FPGA by an array of three columns and three rows.
During idle operation, the KEY ROW signals are driven low by the FPGA and
the KEY COL signals (pulled high by an external resistor) are monitored for
activity by the FPGA. A key-press will generate a high-to-low transition on
the associated column KEY COL signal. This, in turn, will initiate a sequence
of high output levels on the KEY ROW signals to identify which key was
pressed.

Figure 14.11 Circuit diagram of the function, scroll, and selection keys
3V3

3V3

D604

3V3

D620

3V3

D602

3V3

R620

3V3

R621

R622

S603B

S603A

S602B

S602A

S601B

D602

D620

D604

S601A

KEY COL1
KEY COL2
KEY COL3

R623

S606B

S606A

F3 Key

S605B

S604B

S604A

FPGA

S605A

Right Selection Key

F4 Key

KEY ROW1

R624

Left Selection Key

S608B

Scroll-Down Key

S608A

S607B

1
2

S607A

Scroll-Up Key

KEY ROW2

R625

KEY ROW3

F2 Key

F1 Key

The signal at the column side of the switch should be 3.3V. The row side of
the switch should be GND. A successful press will cause transition on
associated KEY_COL signal to low.
Note

One Key Faulty

412

CCTM command 1009 can be used to monitor keypad press and
release events.

If an individual key is faulty:
1.

Use isopropyl alcohol and a soft lens-cleaning cloth to clean the pad
of the tact switch.

Visually inspect both tact switches (A and B) of a key for shortcircuits. Repair if necessary.

Fault Finding of Control Head

Several Keys Faulty

The keys can be grouped into columns and rows of three or two keys, as
illustrated in Figure 14.11.
If one column of keys is faulty:
1.

Visually inspect the associated resistor and diodes for open or shorted
circuits.
F2 key
F4 key
scroll-up key

R620 F1 key
R621 F3 key
D602 right selection key D620 left selection key
scroll-down key

R622
D604

If one row of keys is faulty:
1.

Visually inspect the associated resistor for open or shorted circuits.
F3 key
R623 scroll-up key
F4 key
scroll-down key
right selection key
left selection key

R624 F1 key
F2 key

R625

Figure 14.12 PCB layout of the function, scroll, and selection key circuitry

top side

bottom side

Fault Finding of Control Head

413

14.10 Speaker Faulty
The two speaker lines (SPK+ and SPK–) are connected to the speaker
connector (J104) which is connected to the control-head connector (J103)
through two ferrite beads (L105 and L106).
Figure 14.13 Circuit diagram of the speaker circuitry

Control-Head
Connector
SPKR+

Speaker
Connector
E105

J103
SPKR–
17

J104

E106
2

If the speaker functions only intermittently or the audio level is low:

414

Check the continuity from the speaker connector J104 to pin 18
(SPK+) and pin 17 (SPK–) of the control-head connector J103.

Inspect E105 and E106.

Replace the speaker.

If there is still a fault, go to “Volume Control Faulty” on page 416.

Fault Finding of Control Head

Figure 14.14 PCB layout of the speaker circuitry

top side

bottom side

Fault Finding of Control Head

415

14.11 Volume Control Faulty
The voltage level of the volume control potentiometer is converted to a
digital signal by an analog/digital converter, processed by the FPGA and
transmitted to the main board.
Note

This section only describes faults to the volume control caused by
the control head, which has been established during the initial
servicing tasks by means of elimination test. For fault finding of
the amplifier circuitry of the main board, refer to xxx on page yyy.

Figure 14.15 Circuit diagram of the volume control circuitry
3V3

3V3

8
VCC

FPGA

ADC DO

R105

CH1 U601 DO

VOL WIP DC

RV101

If the volume control works only intermittently, works only at full volume,
or does not work at all:
1.

Check that the voltage between pins CW and WIP of the volumecontrol potentiometer RV1 varies linearly between about 0V and
3.3V.
RV1: 0 to 3.3V

If the voltage is not correct, replace the potentiometer RV1
2.

Send CCTM command 1010 to read the volume potentiometer.
No volume: reading 0 (1V)
Full volume: reading 255 (3.3V)

If the signal is not correct, remove can E100 and replace the
analog/digital converter U601.
If the signal is correct, replace the speaker.

416

Fault Finding of Control Head

Figure 14.16 PCB layout of the volume control circuitry

top side

bottom side

Fault Finding of Control Head

417

14.12 PTT Faulty
The PTT signal from the microphone connector is connected to the FPGA
via a resistor (R25) and relayed to the radio as a digital command.
Figure 14.17 Circuit diagram of the PTT circuitry

Microphone
Connector
FP PTT

FPGA

Note

C108

R25

D106

MIC PTT
4

J106

This section only describes faults to the PTT caused by the control head, which has been established during the initial servicing
tasks by means of elimination test. For fault finding of the ??? circuitry of the main board, refer to xxx on page yyy.

If the PTT is faulty:
1.

With no PTT switch and hookswitch operated, check whether pin 4
of J106 is 4V.
J106 pin 4: 4V

If the signal is correct, continue with step 2.
If the signal is incorrect, inspect R25 for open or shorted contacts.
Repair if necessary. Repeat step 1.
2.

With the PTT switch operated, check whether the same 4V are
pulled to ground on the other side of R25.
If the signal is correct, continue with step 3.
R25: GND

If the signal is incorrect, inspect D106 and C108 for short-circuits.
Repair if necessary.
3.

418

Verify continuity between R25 and the FPGA. Repair PCB track if
possible.

Fault Finding of Control Head

Figure 14.18 PCB layout of PTT circuitry

top side

bottom side

Fault Finding of Control Head

419

420

Fault Finding of Control Head

Spare Parts

Introduction

This section lists all serviceable parts (except PCB components) of the
■

radio body (Figure 15.1, Figure 15.2, and Table 15.1)

■

control head (Figure 15.3 and Table 15.2)

Figure 15.1

Spare parts of the radio body (sheet 1 of 2)

Cx4
D
E

Gx5
H
1@
1!

I
C x2

Spare Parts

421

Figure 15.2

Spare parts of the radio body (sheet 2 of 2)

Gx3
1#x2

1$
1%

1(
2)
1^
1& x2

2!
2@
3641z_01

422

Spare Parts

Table 15.1
Pos.

Spare parts of the radio body

Description

Qty.

IPN

Spares Kit

Cover

–

TMAA22-02 mech. kit

Screw M4 x 16

349-02067-xx

TMAA22-02 mech. kit

Lid

312-01091-xx

–

Bung for aperture for external options connector

302-50000-xx

TMAA22-02 mech. kit

Main seal

362-01109-xx

TMAA22-02 mech. kit

Screw M3 x 10

349-02066-xx

TMAA22-02 mech. kit

Main-board assembly (50W/40W radios)
Main-board assembly (25W radios)

1
1

XMAB34-yyzz TMAA22-34yyzz
XMAB32-yyzz TMAA22-32yyzz

Bung for auxiliary connector

302-50001-xx

TMAA22-02 mech. kit

Seal for RF connector

362-01113-xx

TMAA22-02 mech. kit

Chassis (50W/40W radio)
Chassis (25W radio)

1
1

303-11301-xx
303-11225-xx

–
–

Gap pad for chassis (50W/40W radio only)

369-01048-xx

TMAA22-02 mech. kit
TMAA22-98 gap pad kit

Control-head seal

362-01115-xx

TMAA22-02 mech. kit
TMAA22-07 seals kit

Screw for power connector (50W/40W radio)
Screw for power connector (25W radio)

2
2

346-10022-07
346-10030-08

–

Auxiliary connector [SK101]

240-02022-xx

–

Inner foam seal for auxiliary connector

362-01110-xx

TMAA22-02 mech. kit

Outer foam seal for auxiliary connector

362-01112-xx

TMAA22-02 mech. kit

Lock-nut for auxiliary connector

354-01043-xx

TMAA22-02 mech. kit

Rubber seal for power connector (50W/40W radio)
Rubber seal for power connector (25W radio)

1
1

362-01127-xx
362-01114-xx

TMAA22-02 mech. kit

Power connector [PL100] (50W/40W radio)
Power connector [PL100] (25W radio)

1
1

240-00040-xx
240-00027-xx

–

Gap pad for copper plate (50W/40W radio only)

369-01049-xx

TMAA22-02 mech. kit
TMAA22-98 gap pad kit

Heat-transfer block

308-13147-xx

–

Antenna connector [SK103] (mini-UHF), or
Antenna connector [SK103] (BNC)
(both incl. lock washer and hexagonal nut)

1
1

240-00029-xx
240-00028-xx

–

The characters xx in an IPN stand for the issue number. Items will always be the latest issue at the time the
radio is manufactured.
The characters yy in an IPN or spares kit number stand for the abbreviated frequency band.
For more information, refer to “Frequency Bands” on page 14.
The characters zz in an IPN or spares kit number stand for the type of RF connector (00=BNC, 01=mini-UHF).

Spare Parts

423

Figure 15.3

Spare parts of the control head

Bx2
C

D
Ex4

H
I

G
1)

1%
1#
1^

1&
3451z_02

424

Spare Parts

Table 15.2
Pos.

Spare parts of the control head

Description

Qty.

IPN

Spares Kita

M4 x 12 Taptite screw

349-02058-xx

TMAA22-97

Adaptor flange

349-02067-xx
301-00020-xx

TMAA22-97

Control-head loom (with female-female adaptor)
– female-female adaptor

219-02882-xx
240-00021-41

TMAA22-97

3 x 10 PT screw

346-10030-xx

TMAA22-97

Control-head board

–

TMAA22-96 (x3)

Seal

362-01124-xx

TMAA22-97

Short light pipe

262-00003-xx

TMAA22-97

Long light pipe

262-00004-xx

TMAA22-97

Space-frame

319-30077-xx

TMAA22-97

Speaker clamp

303-50111-xx

TMAA22-97

Speaker

252-00011-xx

TMAA22-97

LCD assembly

–

TMAA22-94 (x3)

Main keypad

311-03124-xx

TMAA22-97

Power keypad

311-03120-xx

TMAA22-97

Concealed microphone

–

TMAA02-07

Front panel assembly

–

TMAA22-97

Knob for volume-control potentiometer

311-01054-xx

TMAA22-97

The characters xx in an IPN stand for the issue number. Items will always be the latest issue at the time the
radio is manufactured.
a. Spares kit TMAA22-97 contains an assembled control head without control-head board, concealed microphone
and LED assembly.

Spare Parts

425

426

Spare Parts

TM9100 mobiles

Chapter 3
Accessories

427

Chapter 3 – Contents
16 TMAA02-08 Keypad Microphone . . . . . . . . . . . . . . . . . . . . . . . . . . .431
16.1 Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 431
16.2 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 433
16.3 Radio Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 434
16.4 Interface Specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 434
16.5 Circuit Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 434
16.6 PCB Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 435
17 TMAA03-02 Security Bracket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .439
17.1 Installing the Security Bracket and Radio . . . . . . . . . . . . . . . . . . . . . . . . 440
17.2 Installation Planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 440
17.3 Removing a Radio from the Security Bracket . . . . . . . . . . . . . . . . . . . . 441
17.4 Replacing the Radio in the Security Bracket . . . . . . . . . . . . . . . . . . . . . 441
17.5 Disassembling the Security Bracket . . . . . . . . . . . . . . . . . . . . . . . . . . . . 442
17.6 Ordering Extra Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 442
18 TMAA04-05 Ignition Sense Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . .443
18.1 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 443
18.2 Radio Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 443
19 TMAA10-01 Desktop Microphone . . . . . . . . . . . . . . . . . . . . . . . . . . .445
19.1 Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 445
19.2 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 445
19.3 Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 446
19.4 Interface Specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 446
19.5 Circuit Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 447
20 TMAA10-02 Handset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .449
20.1 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 449
20.2 Interface Specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 452
21 TMAA10-03 and TMAA10-06 High-Power Remote Speakers . . . . . . . .453
21.1 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 453

428

22 TMAA10-04 Remote PTT Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .455
22.1 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 455
22.2 Radio Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 456
22.3 Interface Specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 457
22.4 Circuit Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 457
22.5 PCB Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 458
23 Installing an Enhanced Remote Kit . . . . . . . . . . . . . . . . . . . . . . . . . .461
23.1 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 461
23.2 Circuit Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 467
23.3 Servicing the Remote Control-Head Installation Parts . . . . . . . . . . . . . . 468
23.4 PCB Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 470
24 TOPA-SV-024 Test Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .477
24.1 Test Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 477
24.2 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 479
24.3 PCB Information (PCB IPN 220-01418-02A) . . . . . . . . . . . . . . . . . . . . 481

429

430

TMAA02-08 Keypad Microphone

PTT key
alphanumeric
keys
left selection key

right selection key

scroll keys

The TMAA02-08 keypad microphone plugs into the
microphone socket on the graphical-display radio control
head, and enables users to make calls to other radios, groups,
or to a PABX or PSTN. The types of call that you can make
depends on the way your radio has been programmed.
As well as the PTT key, there are twelve alphanumeric keys, two
scroll keys, and a left and right selection key on the keypad
microphone. The selection keys and scroll keys duplicate the
keys on the control head.

grommet

The microphone button operates a hookswitch, which is closed
when the microphone is connected to the microphone clip, and
open when the microphone is removed from the microphone
clip. The function of the hookswitch is determined by the
radio programming.

16.1

Operation

16.1.1

Using the Keypad
The 12 alphanumeric keys on the keypad microphone are used to dial call
strings and enter text.
The left selection key
, right selection key
and scroll keys
or
have
the same functions as the left and right selection keys and scroll keys on the
control head.
Pressing an alphanumeric key enters the first character on the key into the
control head display. Subsequent quick presses toggle through the other
characters on the key. Pausing for longer than one second moves the cursor
on to the next place in the dialled string or text message on the control head
display, ready for the next key press.
If the wrong number or character has been selected, use the left selection key on
either the microphone keypad or control head to clear it and move back one.

16.1.2

Using the PTT Key
The PTT key is used for voice transmission.
1.

Select the required channel or group.

Check that the channel is clear. If the green LED is glowing, the
channel is busy and you may not be able to transmit.

TMAA02-08 Keypad Microphone

431

Once the channel is clear (the green LED is off), lift the microphone
off the microphone clip.

Hold the microphone about 5cm (2 inches) from your mouth and
press the PTT key to transmit.

Speak clearly into the microphone and release the PTT key when you
have finished talking.
While you are transmitting, the red LED glows
and the transmit icon appears in the icon bar.

16.1.3

Using the Keypad Microphone to Make a Local or Address-Book Call
There are two ways of making a local call or address-book call:

Example: Making a
local call to your
Dispatcher

■

you can either dial the number for the call you want to make,

■

you can use the radio’s Main menu, or

■

you can use a combination of the two methods, as in the following example.

Select the required channel.

Select Menu>Local Calls.

Press the key corresponding to the first letter of the
name of the person you want to call.
You will have to use short presses to toggle through the characters on the
key until you get the correct one (see “Using the Keypad” on
page 431).

The first name in the Local Calls menu starting
with the keyed letter is displayed.

Scroll through the list of local calls until the call
you want appears.

Press Send.
The call details appear in the display, the red LED
glows and the transmit icon appears in the
icon bar.

432

When the called party responds, lift the microphone off the
microphone clip.

Hold the microphone about 5cm (2 inches) from your mouth and
press the PTT key to transmit.

TMAA02-08 Keypad Microphone

Speak clearly into the microphone and release the PTT key when you
have finished talking.

16.2

Installation

16.2.1

Installing the Microphone
Important

The keypad microphone grommet must be installed whenever the microphone is plugged into the microphone
socket. When installed, the grommet has two functions:
■

to prevent damage to the microphone socket when
there is movement of the microphone cord, and

■

to ensure that the control head is sealed against water,
dust and other environmental hazards.

Make sure the radio is turned off, then plug the keypad microphone
cord into the microphone socket on the radio control head.

Important

The radio will only recognize the presence of the keypad
microphone when the radio is powered on, so that if the
microphone is plugged in after the radio has been powered
on, it will not recognize the keypad microphone. Also, if
the keypad microphone is plugged in on power up but is
later unplugged, then plugged back in, the radio will not
recognize it again until the next power cycle.

Slide the microphone grommet along the microphone cord and push
two adjacent corners of the grommet into the microphone socket
cavity.

Squeeze the grommet and push the remaining corners into position.

Check that the grommet is seated correctly in the cavity.

Figure 16.1

Correct keypad microphone grommet seating

microphone
grommet
control head

16.2.2

Installing the Microphone Clip
Install the microphone clip in the most convenient location for the radio
user. It must be within easy reach of the user, but in such a position that the
microphone PTT key cannot be inadvertently activated or jammed on.

TMAA02-08 Keypad Microphone

433

16.3

Radio Programming
The radio does not need to be programmed to recognize the presence of a
keypad microphone, as this is automatically done when the radio is
powered on.
However, there are a few related fields that should be configured, as
required, to enable the keypad microphone to be used effectively. For
example, in conventional mode there are check boxes called “Selcall Call
Dialling”, “DTMF Call Dialling” and “Phone Patch Call Dialling”. There
is also an option “Conventional Dialling Type” field, where you can
program the radio to dial labels or channels from the default display.
Refer to the online help of the programming application for more information
about these programming options.

16.4

Interface Specification
The following table and diagram summarizes the signals used for the keypad
microphone on the radio’s microphone connector and shows the interface
between the keypad microphone and the radio.
Table 16.1

Keypad microphone connector - pins and signals
Pin

16.5

Signal

Colour
—

Description

RX audio

not connected

13.8V

black

power supply

TXD

green

transmit serial data

PTT

white

PTT and hookswitch

MIC

blue

audio from the microphone

GND

red

ground

RXD

yellow

receive serial data

—

not connected

Circuit Description
The microphone has a standard 12-key telephone keypad which is
connected to a micro-processor. The micro-processor performs the keypad
scanning using eight GPIO lines. When a valid keypress is detected, a serial
command is sent from the microphone.

434

TMAA02-08 Keypad Microphone

16.6

PCB Information
Note

16.6.1

The IPN number on the actual PCB for the keypad microphone
may differ to that shown in the following information.

TMAA02-08 Parts List (PCB IPN 226-00145-04)

Ref.

IPN

Description

Ref.

IPN

Description

C1
C2
C3
C4
C5
C6
C7
C8

018-16100-00
018-16100-00
018-16100-00
015-07220-08
018-16100-00
018-15100-00
018-15100-00
018-15100-00

Cap 0603 100n 16vx7r±10%
Cap 0603 100n 16vx7r±10%
Cap 0603 100n 16vx7r±10%
Cap Cer 1206 2u2 16v X7r
Cap 0603 100n 16vx7r±10%
Cap 0603 10n 50v X7r ±10%
Cap 0603 10n 50v X7r ±10%
Cap 0603 10n 50v X7r ±10%

D1
D2
D3
D4

001-10054-00
001-10054-00
001-10054-00
001-10054-00

Diode SMD BAT54s
Diode SMD BAT54s
Diode SMD BAT54s
Diode SMD BAT54s

R33
R34
R35
R36
R37
R38
R39
R40
R41
R42
R43
R45

038-13680-00
038-14100-10
038-13680-00
038-13680-00
038-13680-00
038-13180-00
038-13180-00
038-13180-00
038-13180-00
038-13680-00
038-13680-00
038-14180-00

Res 0603 680e 1/16w +-5%
Res 0603 1k0 1/16w +-1%
Res 0603 680e 1/16w +-5%
Res 0603 680e 1/16w +-5%
Res 0603 680e 1/16w +-5%
Res 0603 180e 1/16w ± 5%
Res 0603 180e 1/16w ± 5%
Res 0603 180e 1/16w ± 5%
Res 0603 180e 1/16w ± 5%
Res 0603 680e 1/16w +-5%
Res 0603 680e 1/16w +-5%
Res 0603 1k8 1/16w

S18

232-00010-29

Sw Tact 3.85 Stem Red Pcb

DS1
DS2
DS3
DS4
DS5
DS6

008-10004-00
008-10004-00
008-10004-00
008-10004-00
008-10004-00
008-10004-00

LED SMD 0603 Green Ultrabright
LED SMD 0603 Green Ultrabright
LED SMD 0603 Green Ultrabright
LED SMD 0603 Green Ultrabright
LED SMD 0603 Green Ultrabright
LED SMD 0603 Green Ultrabright

U1
U2

002-43010-11
002-14931-00

IC SMD MSP430F1011AIPW Microc
IC L4931CD33 3.3v 250Ma Regso8

274-10010-05

Xtal SMD 32.768KHz Plstc 2MMh

226-00145-04

PCB TMAA-08 K/Pad Micph

240-04020-50

Skt 8w 2x4 Pcb Mtg M/Match

000-10084-71

Xstr BC847BW NPN SOT323

R1
R2
R3
R4
R5
R7
R8
R9
R10
R11
R12
R13
R14
R15
R16
R17
R18
R19
R20
R21
R22
R23
R24
R25
R26
R27
R28
R29
R30
R31
R32

038-14220-00
038-14220-00
038-14220-00
038-14220-00
038-13100-10
038-13100-10
038-15470-10
038-15470-10
038-15100-10
038-15470-10
038-15470-10
038-13180-00
038-12100-10
038-15470-10
038-13180-00
038-13470-00
038-17100-00
038-15120-00
038-14120-10
038-14100-10
038-15470-10
038-13180-00
038-13180-00
038-13680-00
038-13180-00
038-13180-00
038-13180-00
038-13180-00
038-10000-00
038-14120-10
038-13470-00

Res 0603 2k2 1/16w +-5%
Res 0603 2k2 1/16w +-5%
Res 0603 2k2 1/16w +-5%
Res 0603 2k2 1/16w +-5%
Res 0603 100e 1/16w ± 1%
Res 0603 100e 1/16w ± 1%
Res 0603 47k 1/16w +-1%
Res 0603 47k 1/16w +-1%
Res 0603 10k 1/16w +-1%
Res 0603 47k 1/16w +-1%
Res 0603 47k 1/16w +-1%
Res 0603 180e 1/16w ± 5%
Res 0603 10e 1%
Res 0603 47k 1/16w +-1%
Res 0603 180e 1/16w ± 5%
Res 0603 470e 1/16w +-5%
Res 0603 1m 1/16w +-5%
Res 0603 12k 1/16w +-5%
Res 0603 1K2 1%
Res 0603 1k0 1/16w +-1%
Res 0603 47k 1/16w +-1%
Res 0603 180e 1/16w ± 5%
Res 0603 180e 1/16w ± 5%
Res 0603 680e 1/16w +-5%
Res 0603 180e 1/16w ± 5%
Res 0603 180e 1/16w ± 5%
Res 0603 180e 1/16w ± 5%
Res 0603 180e 1/16w ± 5%
Res 0603 Zero 0hm 1/16w ± 5%
Res 0603 1K2 1%
Res 0603 470e 1/16w +-5%

TMAA02-08 Keypad Microphone

435

16.6.2
Ref.

PCB

TMAA02-08 Grid Reference List (PCB IPN 226-00145-04)
Circuit

Top Side Components
Y1
U2
U1
S9
S8
S7
S6
S5
S4
S3
S2
S18
S16
S15
S14
S13
S12
S11
S10
S1
R9
R8
R7
R6
R5
R45
R44
R43
R42
R4
R37
R36
R35
R34
R33
R32
R31
R30
R3
R25
R22
R21
R20
R2
R19
R18
R17
R15
R14
R12
R11
R10
R1
Q2
Q1
J9
J7
J5
J4
J3
J2
J12
J11
J1

436

H5
G4
H5
D4
C3
C4
C5
C6
A3
A4
A5
F4
C1
C2
D2
A2
D3
D5
D6
A6
G5
G5
J4
G3
G5
H4
H4
H3
H3
G6
H3
G3
G3
G3
H3
H6
H6
H6
G5
H3
J4
H3
J4
J6
H4
H4
J4
G6
J4
G5
G5
G3
J5
J6
J5
K3
K5
J5
J2
J5
G5
J3
D3
G2

1G10
1K13
1G9
1F3
1E2
1F2
1F2
1G2
1E1
1F1
1F1
1J7
1E4
1F4
1F4
1G4
1E3
1F3
1G3
1G1
1G6
1G6
1H6
1K6
1H8
1J8
1G7
1J12
1J12
1D7
1J12
1J12
1K12
1H6
1K12
1B9
1B9
1B8
1D7
1K12
1F11
1H5
1B7
1D7
1G7
1F8
1B7
1G8
1B6
1G6
1G6
1K6
1D7
1B8
1B7
1F5 1E5 1G5
1D5 1B5
1F11
1E12
1F7
1G8
1E5
1E4
1J4

TMAA02-08 Keypad Microphone

Ref.

PCB

Circuit

DS6
DS5
DS4
DS3
DS2
DS1
D4
D3
D2
D1
C8
C7
C6
C5
C4
C3
C2
C1

D2
B2
C4
B4
C5
B5
H4
F3
G4
J4
G4
J3
F5
J5
H4
H4
H4
H5

1C3
1C3
1C3
1C2
1C2
1C1
1F8
1K6 1K7
1J7 1H6
1H5
1H6
1H5
1J6
1F8
1J14
1J14
1J12
1H10

Bottom Side Components
TP9
TP8
TP7
TP6
TP5
TP4
TP3
TP20
TP2
TP19
TP18
TP17
TP16
TP15
TP14
TP13
TP12
TP11
TP10
TP1
R41
R40
R39
R38
R29
R28
R27
R26
R24
R23
R16
R13
J8
J6
J14
J13
J10

J3
G5
H5
H3
G3
H3
D4
J5
E5
K5
J6
J6
G4
F3
G3
J5
K5
J3
J4
E5
D5
D5
D5
D5
D5
D6
D6
D6
D5
D4
D5
D4
E5
G6
G4
F5
E3

1F5
1G5
1G5
1K5
1K5
1K5
1E5
1D6
1B4
1D6
1D6
1D5
1J13
1J6
1J6
1B5
1B5
1E5
1E5
1B4
1B4
1B3
1C3
1B3
1C3
1C2
1C2
1C1
1B2
1B1
1B3
1B2
1D5 1B5
1K8
1K8
1J6
1E5 1G5 1F5

16.6.3

Keypad Microphone Board Layout

IPN 226-00145-04 (top side)

IPN 226-00145-04 (bottom side)

TMAA02-08 Keypad Microphone

437

16.6.4

438

Keypad Microphone Board Circuit Diagram

TMAA02-08 Keypad Microphone

TMAA03-02 Security Bracket
The TMAA03-02 security bracket can be used in place of the standard
U-bracket in locations where you want to stop opportunistic removal of the
radio by a third party, or where you want to have a quick release setup that
allows you to swap over radios (e.g. leasing situation). The security bracket
also provides electrical isolation to the radio.
The parts of the TMAA03-02 security bracket are illustrated in Figure 17.1.

Figure 17.1

Parts of the TMAA03-02 security bracket
Mounting rails (see E and F)

Description

Quantity

security bracket cradle base

slide locks

slide lock key

self-tapping screws (10Gx20 hex/
poz) - for fixing security bracket in
place (not pictured)

anti-vibration washers for selftapping screws (not pictured)

1 left
1 right

short mounting rails for TM8100

screws (M4x25 T/T P/T ContiR) for attaching short mounting rails
to TM8100 radio (not pictured)

tall mounting rails for TM8200

screws (M4x30 T/T P/T ContiR) for attaching tall mounting rails to
TM8200 (not pictured)

Note: B and C are pre-assembled

TMAA03-02 Security Bracket

439

17.1

Installing the Security Bracket and Radio

17.2

Installation Planning
Before installing the security bracket, make sure that the site you have
chosen for the installation meets the following criteria:
1.

The site has enough height for the radio to be easily installed
and removed.
The measurements given at the bottom of Figure 17.1 are the heights
of the radios and base only. Allow extra space for manipulation.

Note
2.

You will need more space if you are installing a TM8200 radio.
The site has enough depth for the radio.
Check that the front and rear overhang of the radios will fit where you
are mounting the security bracket.

17.2.1

The site allows for good air circulation, particularly at the rear of
the radio.

Installation Procedure
Important

Note

The security bracket must be securely installed. Otherwise
there is a risk that the whole assembly of the radio and security bracket may become loose over time, or as a result of
serious impact.

Because the some model control heads are taller than others, each
security bracket kit comes with two different heights of mounting
rail and mounting screws, depending on the radio type you
are installing.

Once you have identified a suitable site for the security bracket and radio,
installation is as follows:

440

Use the four self-tapping screws and washers to fix the security
bracket base in place. The base actually has five screw holes available,
but the center screw hole does not need to be used.

Depending on whether you are installing a TM8100 or TM8200
radio, select the correct height mounting rails and screws, and attach
a rail to each side of the bottom of the radio body (two screws per rail,
minimum torque 20in.lbf [2.26N.m]).

To insert the radio, with the mounting rails attached, into the security
bracket base, check that the left and right slide locks are open.

TMAA03-02 Security Bracket

If the slide locks are closed, open them by inserting the slide lock key
into the keyhole. Rotate the key 90° (it will slip into a detent), and
pull.
Two slide lock keys are supplied so that you can either use them both
at once, or so that you can keep one as a spare.

Place the radio over the security bracket base so that the feet of the
mounting rails fit securely into the base.

Close the slide locks by pressing them into the base. You should hear
an audible click as the internal spring lock mechanism engages.

Warning!!

17.3

For continued safe operation, replace and do
not re-use Security Bracket once it has been
involved in a crash greater than 50km/h.

Removing a Radio from the Security Bracket
Remove the radio from the security bracket as follows:

17.4

Open the slide locks by inserting the slide lock key into the keyhole.
Rotate the key 90° (it will slip into a detent), and pull. The pull will
be need to be quite firm to open each slide lock.

Remove the radio and its mounting rails by lifting it up and out of
the security bracket base.

If required, remove the mounting rails from the radio body base by
unscrewing them.

Replacing the Radio in the Security Bracket
To replace the radio in a security bracket, first follow the steps in
“Removing a Radio from the Security Bracket” on page 441, and then
follow from step 2 in “Installing the Security Bracket and Radio” on
page 440.

TMAA03-02 Security Bracket

441

17.5

Disassembling the Security Bracket
Disassemble the security bracket as follows:

17.6

Remove the radio from the security bracket by following the steps in
“Removing a Radio from the Security Bracket” on page 441.

Unscrew the four self-tapping screws holding the security bracket
base in place.

Ordering Extra Parts
The following parts can be ordered separately in case of loss, or in situations
where, for example, one security bracket is installed where several different
radios may be installed at different times.
Part

442

Part Number

Quantity

Security Crdl Key TM8
(slide lock key)

319-60004-XX

Security Crdl Mtg Short TM8
(short mounting rails for TM8100)

319-60002-XX

Scrw M4*25 T/T P/T ContiR
349-02063-XX
(for attaching short mounting rails to TM8100 radio)

Security Crdl Mtg Tall TM8
(tall mounting rails for TM8200)

319-60003-XX

Scrw M4*30 T/T P/T ContiR
(for attaching tall mounting rails to TM8200 radio)

349-02068-XX

TMAA03-02 Security Bracket

TMAA04-05 Ignition Sense Kit

auxiliary connector plug

ignition sense cable

plug into the
radio’s auxiliary
connector

The TMAA04-05 ignition sense kit provides a
mating plug for the radio’s auxiliary connector.
The four metre length of cable from pin 4 of the
plug connects to the vehicle’s ignition signal.
Once the kit is installed, the ignition signal is used
to power up and power down the radio, so that the
radio turns off when the vehicle ignition is off.
This avoids any possibility that the radio may
flatten the vehicle’s battery. When the vehicle
ignition is turned on, the radio either turns on, or
returns to the state that it was in when the vehicle
ignition was turned off.

Important

18.1

18.2

The radio does not meet the IP54 protection standard once
the bung for the auxiliary connector is removed. Therefore,
once the TMAA04-05 ignition sense kit is installed, mount
the radio in areas where it is not exposed to water, dust or
other environmental hazards.

Installation
1.

Connect the auxiliary connector plug to the radio’s
auxiliary connector

Connect the ignition sense cable to the 13.8V signal controlled by the
vehicle’s ignition key.

Radio Programming
Program the AUX GPI3 line to ‘Power Sense (Ignition)’ and active
to ‘High’.
Refer to the online help of the programming application for
more information.

TMAA04-05 Ignition Sense Kit

443

444

TMAA04-05 Ignition Sense Kit

TMAA10-01 Desktop Microphone
The TMAA10-01 desktop microphone is an omnidirectional
dynamic microphone which can be used in dispatch
situations, where the microphone is positioned on a flat
surface. The desktop microphone plugs into the microphone
socket on the radio control head.

grille

microphone
base
TRANSMIT

The desktop microphone has an internal pre-amplifier and an
adjustable sensitivity control on the underside of the desktop
microphone base.

MONITOR

monitor key

PTT key

grommet

19.1

Operation
Hold down the monitor key and check whether the channel is clear.
If the channel is clear, press the PTT key to transmit. Speak clearly into the
microphone and release the PTT key when you have finished talking.
Note

19.2

The monitor key can be locked in the ‘on’ position. To do this,
hold the monitor key down and slide the monitor key towards
you. The monitor key should now be locked on.

Installation
Important

The desktop microphone grommet must be installed
whenever the desktop microphone is plugged into the
microphone socket. When installed, the grommet has two
functions:
■

to prevent damage to the microphone socket when
there is movement of the microphone cord, and

■

to ensure that the control head is sealed against water,
dust and other environmental hazards.

Plug the microphone cord into the microphone socket on the radio
control head.

Slide the grommet along the cord and push two adjacent corners of the
grommet into the microphone socket cavity.

TMAA10-01 Desktop Microphone

445

Squeeze the grommet and push the remaining corners into position.

Check that the grommet is seated correctly in the cavity.

Figure 19.1

Correct desktop microphone grommet seating

microphone
grommet
control head

19.3

Adjustment
Adjust the output sensitivity of the desktop
microphone using R5. R5 is accessible from the
underside of the desktop microphone, as shown.
The microphone sensitivity is set to maximum by
rotating R5 counterclockwise.

adjust R5 here

19.4

Interface Specification
The following table and diagram summarizes the signals used for the desktop
microphone on the radio’s microphone connector and shows the interface
between the desktop microphone and the radio.
Table 19.1

Desktop microphone connector - pins and signals
Pin

446

Signal

Colour

Description

—

not connected

—

not connected

—

not connected

MIC_PTT

yellow

PTT

MIC_AUD

red

audio from the microphone

AGND

bare

analog ground

—

not connected

—

not connected

TMAA10-01 Desktop Microphone

Figure 19.2 Desktop microphone
to radio interface
.

19.5

Circuit Description
The desktop microphone uses a dynamic microphone capsule and contains
a pre-amplifier (Q1) to boost the microphone level to that required by the
radio. Power for the pre-amplifier is provided by the electret microphone
bias circuit within the radio. R5 is used to adjust the gain.
PTT and hookswitch signals are combined onto one line and fed to the
control head PTT input of the radio.

TMAA10-01 Desktop Microphone

447

448

TMAA10-01 Desktop Microphone

TMAA10-02 Handset
The TMAA10-02 handset provides the user with privacy and also
improves the audio quality in noisy environments. The handset
uses a dynamic microphone capsule, so for TM8100 radios, the
TMAA02-06 support kit for concealed and dynamic microphones
needs to be installed.

handset

pushbutton
locking
cradle

radio to
handset cord

mounting
plate

When your radio receives a call and the handset is mounted in
its locking cradle, the radio unmutes and you can hear the call
from your radio’s internal speaker and from any connected
remote speaker.
If you remove the handset from its cradle when you receive a call,
the radio unmutes and you can hear the call from your radio’s
internal speaker, from any connected remote speaker and from the
handset earpiece.
Using private handset mode, the radios internal and external speakers
are muted and the call can only be heard from the handset earpiece.

grommet

20.1

Installation

20.1.1

Handset Wiring
1.

Drill a hole in the chosen mounting surface for the radio to handset
cord and pass the cord through the hole.

Prepare the radio to handset cord, as follows.
■

Cut the radio to handset cord to the required length.

■

Strip away about 60mm (2 inches) of the cable outer sheath on the
end without a connector.

■

Cut off the exposed orange, red, black and bare wires.

■

Strip about 6mm (0.2 inches) of the coating off each of the five
remaining wires.

Secure the radio to handset cord in the handset PCB P-clip b, as
shown in the diagram.

Connect the five wires to the handset PCB connector c.

TMAA10-02 Handset

449

Table 20.1

Handset PCB connector wiring
Handset PCB
Connector

b
c
de
20.1.2

20.1.3

white
or violet

blue

brown

yellow

green

Handset Installation
1.

Press the pushbutton and remove the handset from the locking cradle.

Disassemble the locking cradle by removing the four locking cradle
screws.

Screw the handset mounting plate to the required mounting surface.
Note that mounting screws are not provided in this kit.

Clamp the top part of the locking cradle onto the mounting plate,
and secure it with the four locking cradle screws.

Connecting the Handset to the Radio
Important

450

fgh

Colour Reference

The handset microphone grommet must be installed whenever the handset to radio cord is plugged into the microphone
socket. When installed, the grommet has two functions:
■

to prevent damage to the microphone socket when there
is movement of the microphone cord, and

■

to ensure that the control head is sealed against water,
dust and other environmental hazards.

Plug the radio to microphone cord into the microphone socket on
the radio control head.

Slide the grommet along the cord and push two adjacent corners of the
grommet into the microphone socket cavity.

Squeeze the grommet and push the remaining corners into position.

Check that the grommet is seated correctly in the cavity.

TMAA10-02 Handset

Figure 20.1

Correct handset microphone grommet seating

microphone
grommet
control head

20.1.4

Radio Programming
Dynamic microphone support must be enabled in the UI Preferences form
of the radio’s programming application, so that audio is optomized for
dynamic microphones. Refer to the online help of the programming
application for more information.

Dynamic
Microphone
Support

Table 20.2

Handset settings in the UI Preferences form
(TM8100 Programming Application)

Field

Setting

Audio Setup
Table 20.3

Enable Options Board Preamp selected
Handset settings in the UI Preferences form
(TM8200, TM9000/TP9000 Programming Application)

Field

Setting

Audio>Audio Setup

Private Handset
Mode

Selected/Cleared

Dynamic Mic Support

selected

If private handset mode is required, the radio needs to be programmed to
mute the audio power amplifier when the handset is out of the cradle.
The audio path is then only through the RX AUDIO line to the handset
earpiece.
The following table shows the settings required in the Programmable I/O
form of the radio’s programming application. Refer to the online help of the
programming application for more information.
Note

Table 20.4
Pin

If private handset mode is programmed, then no audio will be
heard from the speakers if the handset is unplugged.

Handset settings in the Programmable I/O form
Direction

CH_GPIO1 Input

Label
None

Action

Active

Force Audio PA Off High

Debounce
25

Signal State
None

Mirrored To
None

TMAA10-02 Handset

451

20.2

Interface Specification
The following table and diagram summarizes the signals used for the handset
on the radio’s microphone connector and shows the interface between the
handset and the radio.

Table 20.5

Handset microphone connector - pins and signals
Pin

Figure 20.2

452

Signal

Handset PCB
Connector

Colour Description

RX_AUD

brown

receive audio to handset

—

not connected

—

not connected

PTT

white

PTT and hookswitch

MIC

yellow

audio from the handset to dynamic-mic
support board

GND

green

analog ground

—

not connected

CH_GPIO1 3

blue

programmable line controlling private mode

Handset to. radio interface

TMAA10-02 Handset

TMAA10-03 and TMAA10-06
High-Power Remote Speakers

remote speaker cable

The TMAA10-03 remote speaker (for the 25W radio) and
the TMAA10-06 remote speaker (for the 50W/40W radio)
are installed in parallel with the radio’s existing internal
speaker. The remote speaker can then be installed at some
distance from the radio, or it can be used to increase the
volume of the audio from the radio’s existing internal speaker.

mounting
bracket

The remote speaker cable is terminated with two receptacles.
These receptacles are different between the TMAA10-03 and
the TMAA10-06 remote speakers.

receptacles

Two spare receptacles are included with the remote speaker,
along with four mounting screws and washers.

21.1

Installation

21.1.1

Remote Speaker Mounting
1.

Choose a mounting position for the remote speaker where it will not
interfere with the operation of any of the vehicle controls.

Remove the remote speaker from the mounting bracket and use the
screws and washers provided to fix the mounting bracket securely in
the chosen location.

Important

Check before drilling that the drill will not damage any
components or wiring behind the mounting location.

■

If mounting the bracket onto a metal surface, drill two 3.5mm
(0.14 inch) holes in the appropriate locations and secure the
bracket with the supplied self tapping screws.

■

If mounting the bracket to any other material, such as plastic, drill
two 4.5mm (0.18 inch) holes and attach the bracket with screws
and captive nuts, or similar.

Attach the speaker to the mounting bracket using the thumbscrews.

Run the free end of the speaker cable to the radio power cable and
install the two receptacles in the power connector, as described in the
“Power Connector Wiring” procedure.

Important

Check that the speaker cable is protected from engine heat,
sharp edges and from being pinched or crushed.

TMAA10-03 and TMAA10-06 High-Power Remote Speakers

453

21.1.2

Power Connector Wiring
Insert the remote speaker receptacles into the power connector socket, as
shown in the diagrams below.
Note

The positive remote speaker wire has a white stripe.
With the TMAA10-03 remote speaker (25 W radio), insert the
the positive remote speaker wire into the position nearest to the
red wire.
With the TMAA10-06 remote speaker (50 W/40 W radio),
insert the positive remote speaker wire into the upper position
(marked “3”).

.Figure 21.1

Power connector wiring of the TMAA10-03 remote speaker

+13.8V
(red)
remote
speaker cable

speaker +
speaker –

power
connector

ground
(black)

.Figure 21.2

Power connector wiring of the TMAA10-06 remote speaker
speaker – (to pin 2)

+13.8V
(red)
remote
speaker cable
ground
(black)

454

power
connector

speaker + (to pin 3)

TMAA10-03 and TMAA10-06 High-Power Remote Speakers

TMAA10-04 Remote PTT Kit

remote PTT

extension lead for
remote PTT

auxiliary
connector plug

Important This kit does not meet the IP54 protection standard. Care must be taken when
a radio with a TMAA10-04 kit
installed is being operated in an environment where there is water, dust or
other environmental hazards.

remote microphone
mounting options

Installation
Important

22.1.1

The TMAA10-04 kit uses a conveniently mounted remote
PTT key for PTT operation. When the remote PTT is
activated, the remote microphone is used for communication.
There are three mounting options for the remote microphone
and an extension lead is provided for the remote PTT in the
TMAA10-04 kit.

remote microphone

22.1

The TMAA10-04 remote PTT kit plugs into the radio’s
auxiliary connector. This kit uses the remote electret
microphone to replace communication through the usual
rugged microphone. The rugged microphone can still
provide hookswitch operation, if this is required.

Care should be taken to avoid routing any cables near vehicle pedal controls, steering column and other moving parts.

Installing the Remote Microphone
1.

Choose one of the three mounting options provided for the remote
microphone and determine its most appropriate location.
The mounting position of the microphone should be no more than
50cm (20 inches) from the user’s mouth.

Route the remote microphone cable so as not to distract the driver.

Mount the remote microphone in the chosen location and check
that the microphone and cable are clear of all the usual movements
performed by the user.

TMAA10-04 Remote PTT Kit

455

22.1.2

Installing the Remote PTT
Important
1.

The remote PTT must be operable from a normal
driving position.

Secure the remote PTT in position using the velcro strap and plug the
remote PTT cord into the remote PTT extension lead.
A common position for the remote PTT is on the gear lever of
the vehicle.

Check that the cord and lead do not interfere with the safe operation
of the vehicle.

22.2 Radio Programming
22.2.1

Remote PTT Settings in the PTT Form
The following table shows the settings required in the PTT form of the
programming application. Some of these settings are default settings and
may not need to be changed. Refer to the online help of the programming
application for more information.
Note

If hookswitch operation is programmed for the rugged microphone and the Inhibit PTT Transmission When Mic On Hook
field is selected in the PTT tab of the PTT form, then the handsfree remote PTT cannot transmit when the rugged microphone
hookswitch is closed (the microphone is on the microphone clip).

Table 22.1

Remote PTT settings in the PTT form, External PTT (1) tab

Field

Setting

Advanced EPTT1

22.2.2

Audio Source

AUX MIC

The Programmable I/O form setting for AUX_GPIO4 must have
the default programming settings and the AUX_GPIO4 pullup
resistor on the radio main PCB must be set for the factory default
of 3.3V (R769 fitted).

Remote PTT settings in the Programmable I/O form, Digital tab
Direction

AUX_GPI1

Voice

Remote PTT Settings in the Programmable I/O Form
Note

Table 22.2

PTT Transmission Type

Label

Action

Active

Debounce

Signal State

Mirrored To

Input

None

External PTT 1 Low

None

AUX_GPIO4 None

None

No Action

None

456

TMAA10-04 Remote PTT Kit

None

22.3

Interface Specification
The following table and diagram summarizes the signals used for the remote
PTT and hands-free kits on the radio’s auxiliary connector and shows the
interface between the kits and the radio.
Table 22.3

Auxiliary connector - pins and signals
Pin

B
J
C
1)
D
1!
E
1@
F
1#
G
1$
H
1%
I
rear view

Figure 22.1

22.4

Signal name

Description

+13V8_SW

power to hands-free microphone preamplifier

AUX_GPIO4

reference voltage to pre-amplifier
regulator

AUX_GPI1

PTT signal from hands-free kit

AUX_MIC_AUD microphone audio to the radio

AGND

analog ground

TMAA10-04/TMAA10-05
to radio interface
.

Circuit Description
The remote microphone signal is amplified by a pre-amplifier in the
auxiliary connector plug. The power supply to this amplifier is provided by
the +13.8V supply on the auxiliary connector. This supply is filtered and
regulated down to approximately 3.3V. The reference voltage for the
regulator is provided by AUX_GPIO4 line.
The remote microphone signal is fed via AUX_MIC_AUD and an input
selector to the radio’s internal microphone amplifier. The microphone input
selected depends on the PTT source used to make the call. If the remote PTT
is used, then AUX_MIC_AUD is selected. If the control head microphone
PTT is used, then CH_MIC_AUD is selected. Test points for all other
auxiliary connections are provided on the auxiliary connector plug PCB to
facilitate the connection of other devices or signals e.g ignition switch signal.

TMAA10-04 Remote PTT Kit

457

22.5

PCB Information

22.5.1

TMAA10-04 Parts List (PCB IPN 220-01711-01)

Ref.

IPN

Description

C2
C3
C4
C6
C7

015-26330-08
018-15100-00
015-26330-08
015-26100-08
015-26100-08

Cap Cer 0805 330n 5% 10v X7r
Cap 0603 10n 50v X7r +-10%
Cap Cer 0805 330n 5% 10v X7r
Cap Cer 0805 100n 10% X7r 50v
Cap Cer 0805 100n 10% X7r 50v

Q1
Q2
Q3
Q4

000-10084-71
000-10085-71
000-10084-71
000-10084-71

Xstr BC847BW NPN SOT323
Xstr SMD BC857BW PNP SOT323
Xstr BC847BW NPN SOT323
Xstr BC847BW NPN SOT323

R1
R3
R4
R6
R13
R16
R17
R18
R19

038-14220-00
038-14390-10
038-15470-10
038-15330-10
038-15100-10
038-15470-10
038-15150-00
038-15100-10
038-15100-10

Res 0603 2k2 1/16w +-5%
Res 0603 3k9 1%
Res 0603 47k 1/16w+-1%
Res 0603 33k 1%
Res 0603 10k 1/16w +-1%
Res 0603 47k 1/16w+-1%
Res 0603 15k 1/16w +-5%
Res 0603 10k 1/16w +-1%
Res 0603 10k 1/16w +-1%

Ref.

IPN

Description

219-00305-00 cable
220-01711-01 Pcb HFree
236-00001-00 Sw Ptt W/Cbl & Strap
240-06010-18 Conn 15w Hood/Cvr Drng MDJ15
252-00010-72 Mic Electret Unidir 2.5mm Plg
402-00006-01 F/Inst TMAA10-04/TMAA10-05 Eng

458

TMAA10-04 Remote PTT Kit

Pre-Amplifier Board Layout

IPN 220-01711-01 (top side)

IPN 220-01711-01 (bottom side)

22.5.2

TMAA10-04 Remote PTT Kit

459

22.5.3

460

Pre-Amplifier Board Circuit Diagram

TMAA10-04 Remote PTT Kit

Installing an Enhanced Remote Kit
The control head of a graphical-display radio can be installed remotely from
the radio body. The diagram below shows the parts used for this installation.

control-head interface

remote U-bracket

TMAA03-03 remote
TMAA04-01 remote cable
control-head back
(includes remote U-bracket)

Note

23.1

TMAC34-0T (TM8200) or
TMAC34-1T(TM9100)
torso interface

Although the torso interface is similar in appearance to the dualRJ45 on the telemetry radio, the control head on the telemetry
radio cannot be used for remote installation.

Installation
Warning!!

Mount the remote U-bracket with the remote
control-head assembly and the U-bracket with
the radio body securely. These units must not
break loose in the event of a collision. Unsecured radio units are dangerous to the
vehicle occupants.

Caution

Observe the installation warnings and safety regulations in the installation procedures of the radio.

Important

This equipment contains devices which are susceptible to
damage from static discharges. Refer to “ESD Precautions”
on page 103 for more information.

Note

Torx T10 and T20 screwdrivers are required for most of the screws
in this installation.

The circled numbers in the following sections refer to the items in Figure 23.1
on page 462.

Installing an Enhanced Remote Kit

461

23.1.1

Overview
Installing the control head remotely is done in six steps:

23.1.2

Remove the control head from the radio body, if necessary.

Install the torso interface b onto the radio body.

Mount the remote U-bracket d in the required position.

Install the control-head interface c onto the control head and install
the remote control-head assembly in the remote U-bracket.

Mount the U-bracket in the required position and install the radio
body in the U-bracket.

Route the remote cable e between the remote control-head
assembly and the radio body.

Parts Required
The following diagram identifies the parts for remote controlhead installation and shows how they fit together.

Figure 23.1

Parts for remote control-head installation

1!
j

e
i
h
b

c
f
g

d
b
c
d
e
f
g

462

torso interface
control-head interface
remote U-bracket
remote cable
self-drilling screw
thumb screw

Installing an Enhanced Remote Kit

h
i
j
1)
1!
1@

RJ45 bung
control-head interface loom
torso-interface loom
earthing tag
earthing-tag screw
remote cable grommets

23.1.3

Removing the Control Head from the Radio Body (if necessary)
Caution

During this procedure, take care that the controlhead seal is not damaged. Damage to this seal
reduces environmental protection.

On the underside of the radio,
insert a 5mm (3/16 inch) flatbladed screwdriver between the
control head and the control-head
seal, in the positions shown.

lever point
control-head seal
indication of
lever point

Insertion points and are lever
points and are indicated on the
radio chassis by a dot-dash-dot pattern (•

– •).

Use the screwdriver to lift the control head off the chassis clip, then
repeat in the other position.

Unplug the control-head loom from the radio body.
The control head is now separate from the radio body.

23.1.4

Installing the Torso Interface
The torso interface must be installed onto the radio body, in place of the
control head.
1.

Screw the solder tag 1) onto one of the screw bosses on the
radio chassis.

Plug the torso-interface loom j
onto the control-head connector.

Insert the bottom edge of the
remote control head b onto the
two clips in the front of the radio
chassis, then snap into place.

Remove one of the bungs h
covering the RJ45 connectors.
h
The remote cable e will plug
into this connector once the installation is complete.

j
b

If the remote cable is not installed in the RJ45 cavity, then
the RJ45 bung must be installed. This ensures that the torso
interface is sealed against water, dust and other
environmental hazards.

Installing an Enhanced Remote Kit

463

23.1.5

Mounting the Remote U-Bracket
The remote U-bracket with its self-drilling screws, is used to install the remote
control-head assembly on the dashboard or on any sufficiently flat surface.

23.1.6

Caution

When drilling holes in the vehicle, check that drilling
at the selected points will not damage existing wiring.

Important

Check that the remote U-bracket is not distorted when the
screws are tightened.

Drill any holes required for cables and install suitable grommets or
bushings in the holes.

If precise positioning is required, predrill 3mm (1/8 inch) pilot
holes for the self-drilling screws. Reduce the hole size in metal that
is less than 1mm (1/32 inch) thick.

Screw the remote U-bracket in the chosen mounting position using the
self-drilling screws provided. Use all four screws provided.

Installing the Control-Head Interface
With the control head separated from the radio body, the control-head
interface c must be installed on the rear of the control head.
1.

Undo the two Torx T-20 screws
on the adaptor flange of the
control head, and remove the
adaptor flange.

adaptor flange

Unplug the control-head loom.

space-frame seal

The adaptor flange and controlhead loom are not used for the
remote control-head installation.
Keep the two screws for step (4).
3.

Plug the control-head interface
loom i into the connector on
the control head.

Important
4.

Changing the
Remote U-Bracket
Orientation

464

control head loom

control head

When fitting the control-head interface to the controlhead, be careful not to damage the space-frame seal.

Use the two screws from step (2) to fit the control-head interface to
the control head through the two screw holes at the rear of the
control-head interface.

The control-head interface is configured for installation with the RJ45
socket facing downwards (U-bracket below control head, as in Figure 23.1).
If the RJ45 socket is required to face upwards (control head hanging from

Installing an Enhanced Remote Kit

U-bracket), the control-head interface loom i must be moved, so that it
can reach the control head connector.
To move the control-head interface loom:

Installing the
Remote ControlHead Assembly in
the Remote
U-Bracket

Undo the seven Torx T-10 screws on the control-head board, and
remove the control-head interface board from the
control-head interface.

Change the control-head interface loom i to the
opposite connector.

Reinstall the control-head interface board.

Position the control-head assembly in the remote U-bracket and
position it for a good viewing angle.

Note
2.

23.1.7

Adjusting the contrast on the control-head display may also
improve its readability.
Screw the remote control-head assembly into position using the two
thumb screws provided.

Mounting the U-Bracket and Installing the Radio Body

Mounting the
U-Bracket

Install the U-bracket on any sufficiently flat surface, using self-drilling screws
and washers.
Caution

When drilling holes in the vehicle, check that drilling
at the selected points will not damage existing wiring,
petrol tanks, fuel lines, brake pipes or battery cables.

Important

When mounting the U-bracket, check whether the
mounting surface needs to be reinforced.

Important

Install the U-bracket using at least four screws.

If the U-bracket is being mounted over a curved surface, bend the
U-bracket tabs slightly, to match the surface shape.

Drill any holes required for cables and install suitable grommets or
bushings in the holes.

Important
3.

Check that the U-bracket is not distorted when the screws
are tightened.

If precise positioning is required, predrill 3mm (1/8 inch) pilot
holes for the self-drilling screws. Reduce the hole size in metal that
is less than 1mm (1/32 inch) thick.

Installing an Enhanced Remote Kit

465

Installing the Radio
Body in the
U-Bracket

23.1.8

Screw the U-bracket in the chosen mounting position using the selfdrilling screws washers.

Connect the antenna and power cables to the rear of the radio.

Position the radio body in the U-bracket so that the holes in the
U-bracket line up with the holes in the radio chassis.

Screw the radio into position using the four thumb screws.

Connecting the Remote Cable
Caution

Installing the
Remote-Cable
Grommets

When drilling holes in the vehicle, check that drilling
at the selected points will not damage existing wiring,
petrol tanks, fuel lines, brake pipes or battery cables.

Drill any holes required for cables and install suitable grommets or
bushings in the holes.

Plug one end of the remote cable into the control-head interface.

Run the remote cable to the torso interface and plug it into the
RJ45 connector without a bung.

Install both the remote cable grommets, using the following procedure.
Important

The remote cable grommets must be installed whenever the
remote cable is plugged into the RJ45 sockets. When
installed, the grommets have two functions:
■

to prevent damage to the RJ45 sockets when there is
movement of the remote cable, and

■

to ensure that the radio and remote control-head assembly
is sealed against water, dust and other environmental
hazards.

Slide the grommet along the remote cable and push two adjacent
corners of the grommet into the RJ45 socket cavity.

Squeeze the grommet and push the remaining corners into position.

Check that the grommet is seated correctly in the cavity.

Figure 23.2

Correct remote cable grommet seating

microphone
grommet
control head

466

Installing an Enhanced Remote Kit

23.2

Circuit Description
Figure 23.3 shows a block diagram of the remote control-head installation.
Both control heads contain a circuit board with audio amplifiers and RS485 driver components.

Figure 23.3

Block diagram of remote control-head installation

Installing an Enhanced Remote Kit

467

23.3

Servicing the Remote Control-Head Installation Parts

23.3.1

Disassembling the Torso Interface
Disassemble only as much as is necessary to replace the defective parts.
Re-assembly is carried out in reverse order of disassembly.

Figure 23.4

Release the clip of the PCB bracket E and remove the controlhead board B .

Disconnect the torso-interface loom C .

Unscrew the four PT type screws D and remove the PCB bracket E.

Parts of the torso interface
Description

B
C
D
E
F
G
H

C
Dx4
E

IPN

control-head board
torso-interface loom

219-02882-XXa

3 x 8 PT screw (x4)

346-10030-XXa

PCB bracket

302-10063-XXa

front panel

316-06843-XXa

label

365-01751-XXa

RJ45 bung

302-50002-XXa

Contact Technical Support for the exact IPN.

G
H

468

Installing an Enhanced Remote Kit

23.3.2

Disassembling the Control-Head Interface
Disassemble only as much as necessary to replace the defective parts or to
swap the Micromatch connector loom. Re-assembly is carried out in reverse
order of disassembly.

Figure 23.5

Unscrew the seven PT type screws B and remove the PCB C.

Remove the control-head interface loom (not illustrated).

Parts of the control-head interface

Bx7

Description

B
C
D

3 x 8 PT screw (x7)

IPN
346-10030-XXa

control-head interface PCB
control-head interface

316-06842-XXa

control-head interface loom 219-02914-XXa

C
a

Contact Technical Support for the exact IPN.

Installing an Enhanced Remote Kit

469

23.4

PCB Information

23.4.1

TMAA03-03 Control-Head Interface (PCB IPN 220-01721-02)

Parts List
Ref.

IPN

Description

Ref.

IPN

Description

C100
C101
C102
C103
C110
C300
C301
C310
C311
C320
C400
C401
C410
C411
C420
C421
C422
C423
C430
C500
C600
C601
C610
C611
C612
C700
C701
C702
C703
C704
C705
C706
C707
C708
C710
C711
C712
C730
C731
C732
C733
C734
C735

018-14101-00
018-14101-00
015-02470-06
015-02470-06
018-16100-00
015-06470-01
015-07220-08
015-26100-08
015-07220-08
016-09100-07
018-16100-00
015-07220-08
018-16100-00
018-13100-00
018-16100-00
018-13100-00
015-07220-08
015-07220-08
015-07220-08
015-26100-08
015-26100-08
015-26100-08
015-26100-08
015-07220-08
015-07220-08
015-26100-08
015-07220-08
015-07220-08
015-06470-01
018-16100-00
018-16100-00
018-13220-00
015-06470-01
015-07220-08
015-07220-08
015-07220-08
015-07220-08
015-26220-18
015-26220-18
018-14100-00
018-14100-00
015-07220-08
015-07220-08

Cap 0603 1n 50v NPO ±5%
Cap 0603 1n 50v NPO ±5%
Cap Cer 1210 47p NPO 500v
Cap Cer 1210 47p NPO 500v
Cap 0603 100n 16v x7r + - 10%
Cap Cer 1206 470n X7r 20% 50v
Cap Cer 1206 2u2 16v X7r
Cap Cer 0805 100n 10% X7r 50v
Cap Cer 1206 2u2 16v X7r
Cap Elec SMD 100u 35v Loesr
Cap 0603 100n 16v x7r + - 10%
Cap Cer 1206 2u2 16v X7r
Cap 0603 100n 16v x7r + - 10%
Cap 0603 100p 50v NPO ±5%
Cap 0603 100n 16v x7r + - 10%
Cap 0603 100p 50v NPO ±5%
Cap Cer 1206 2u2 16v X7r
Cap Cer 1206 2u2 16v X7r
Cap Cer 1206 2u2 16v X7r
Cap Cer 0805 100n 10% X7r 50v
Cap Cer 0805 100n 10% X7r 50v
Cap Cer 0805 100n 10% X7r 50v
Cap Cer 0805 100n 10% X7r 50v
Cap Cer 1206 2u2 16v X7r
Cap Cer 1206 2u2 16v X7r
Cap Cer 0805 100n 10% X7r 50v
Cap Cer 1206 2u2 16v X7r
Cap Cer 1206 2u2 16v X7r
Cap Cer 1206 470n X7r 20% 50v
Cap 0603 100n 16v x7r + - 10%
Cap 0603 100n 16v x7r + - 10%
Cap 0603 220p 50v NPO±5%
Cap Cer 1206 470n X7r 20% 50v
Cap Cer 1206 2u2 16v X7r
Cap Cer 1206 2u2 16v X7r
Cap Cer 1206 2u2 16v X7r
Cap Cer 1206 2u2 16v X7r
CAP CER 0805 220N 10% X7R 50V
CAP CER 0805 220N 10% X7R 50V
Cap 0603 1n 50v X7r ±10%
Cap 0603 1n 50v X7r ±10%
Cap Cer 1206 2u2 16v X7r
Cap Cer 1206 2u2 16v X7r

E101
E102
E103
E105
E710
E711
E730
E731

057-10081-06
057-10600-05
057-10600-05
057-10081-06
057-10600-05
057-10081-06
057-10081-06
057-10081-06

Ind 1806 Blm41p750s Emi Supr
Ind 0603 Blm11p600s .5a F/Bead
Ind 0603 Blm11p600s .5a F/Bead
Ind 1806 Blm41p750s Emi Supr
Ind 0603 Blm11p600s .5a F/Bead
Ind 1806 Blm41p750s Emi Supr
Ind 1806 Blm41p750s Emi Supr
Ind 1806 Blm41p750s Emi Supr

J100
J200
J201

240-00016-00
240-10000-11
240-10000-11

Conn RJ45 Shld 8P8C LP RA TH
Conn SMD 18w Skt M/Match
Conn SMD 18w Skt M/Match

L712
L730
L731

057-10100-65
057-10010-02
057-10010-02

Ind SMD Pwr Cdrh6D38 100UH .65
Ind SMD Pwr CDRH74 10UH 1.8A
Ind SMD Pwr CDRH74 10UH 1.8A

Q610
Q720
Q721

000-10084-71
000-10084-71
000-10442-70

Xstr BC847BW NPN SOT323
Xstr BC847BW NPN SOT323
Xstr SI4427DY PCH Pwr MFET SO8

D100
D101
D102
D103
D104
D110
D201
D211
D300
D720
D730
D731

001-10000-99
001-10000-99
001-10000-99
001-10000-99
001-10000-99
001-10084-91
001-10000-99
001-10000-99
001-10000-99
001-10841-10
001-10014-03
001-10014-03

Diode SMD BAV99 D-Sw SOT23
Diode SMD BAV99 D-Sw SOT23
Diode SMD BAV99 D-Sw SOT23
Diode SMD BAV99 D-Sw SOT23
Diode SMD BAV99 D-Sw SOT23
Diode SMD BZX84C9V1 Zen SOT23
Diode SMD BAV99 D-Sw SOT23
Diode SMD BAV99 D-Sw SOT23
Diode SMD BAV99 D-Sw SOT23
Diode SMD BZX84C11v ZEN SOT23
Diode SMD MBRS140T3 Sch
Diode SMD MBRS140T3 Sch

E100

057-10081-06

Ind 1806 Blm41p750s Emi Supr

R100
R110
R200
R201
R202
R210
R211
R212
R300
R301
R320
R401
R402
R410
R411
R412
R420
R421
R422
R430
R431
R441
R442
R501
R510
R511
R600
R601
R602
R603
R604
R605
R606
R607
R608
R609
R611

038-13100-00
038-15100-00
038-13100-00
038-13100-00
038-13100-00
038-13100-00
038-13100-00
038-13100-00
038-14120-00
038-13220-00
036-00000-00
038-14470-00
038-14470-00
038-15150-00
038-16150-00
038-13100-00
038-15330-00
038-15220-00
038-12470-00
038-14220-00
038-14220-00
038-14470-00
038-14470-00
038-15100-00
038-13120-00
038-10000-00
038-15100-00
038-16470-00
038-10000-00
038-10000-00
038-10000-00
038-10000-00
038-15100-00
038-15100-00
038-15100-00
038-15100-00
038-15100-00

Res 0603 100e 1/16w ± 5%
Res 0603 10k 1/16w +-5%
Res 0603 100e 1/16w ± 5%
Res 0603 100e 1/16w ± 5%
Res 0603 100e 1/16w ± 5%
Res 0603 100e 1/16w ± 5%
Res 0603 100e 1/16w ± 5%
Res 0603 100e 1/16w ± 5%
Res 0603 1k2 1/16w +-5%
Res 0603 220e 1/16w +-5%
Res 1206 0e 5% 0.125w
Res 0603 4k7 1/16w +-5%
Res 0603 4k7 1/16w +-5%
Res 0603 15k 1/16w +-5%
Res 0603 150k 1/16w +-5%
Res 0603 100e 1/16w ± 5%
Res 0603 33k 1/16w +-5%
Res 0603 22k 1/16w +-5%
Res 0603 47e 1/16w ± 5%
Res 0603 2k2 1/16w +-5%
Res 0603 2k2 1/16w +-5%
Res 0603 4k7 1/16w +-5%
Res 0603 4k7 1/16w +-5%
Res 0603 10k 1/16w +-5%
Res 0603 120e 1/16w ± 5%
Res 0603 Zero 0hm 1/16w ± 5%
Res 0603 10k 1/16w +-5%
Res 0603 470k 1/16w ± 5%
Res 0603 Zero 0hm 1/16w ± 5%
Res 0603 Zero 0hm 1/16w ± 5%
Res 0603 Zero 0hm 1/16w ± 5%
Res 0603 Zero 0hm 1/16w ± 5%
Res 0603 10k 1/16w +-5%
Res 0603 10k 1/16w +-5%
Res 0603 10k 1/16w +-5%
Res 0603 10k 1/16w +-5%
Res 0603 10k 1/16w +-5%

470

Installing an Enhanced Remote Kit

Ref.

IPN

Description

R612
R701
R710
R720
R721
R722
R730
R731

038-14470-00
038-16120-00
036-13100-00
038-15100-00
038-14220-00
038-14470-00
038-12470-00
038-12470-00

Res 0603 4k7 1/16w +-5%
Res 0603 120k 1/16w +-5%
Res M/F SMD 0805 100e 5%
Res 0603 10k 1/16w +-5%
Res 0603 2k2 1/16w +-5%
Res 0603 4k7 1/16w +-5%
Res 0603 47e 1/16w ± 5%
Res 0603 47e 1/16w ± 5%

U300
U310
U400
U500
U600
U610
U700

002-12523-17
002-14931-00
002-19120-00
002-13483-00
002-15595-00
002-10126-71
002-13001-00

IC LM317l Reg T0252 0.5a
IC L4931CD33 3.3v 250Ma Regso8
IC TS912ID Cmos R2R Opamp
IC XCVR RS485 LTD SLEW RATE 3V
IC 74AHC595 8bit Shiftreg Tsop
IC SMD DS1868 Dgtl Pot Tsop20
IC TPA3001 20W Mono PA TSSOP24

220-01721-02

PCB MFX Head Remote

IPN

Description

219-02914-00
302-10062-00
302-05263-00
316-06842-00
346-10030-08
349-00060-00
353-05007-00
354-01052-00

Loom MFX Remote Head
Brkt Remote Head TM8200
Brkt U Thumb Scrw TMA
Pnl Rear TM8200 MF2
Scrw P/T Wn1412 Kc30x08 Zbc
Scrw 10GX20 SLFDRL Hex/Poz TMA
Wshr Rubber M4*19*1.0 S/A
Fsnr Bush PSM SHK-B-M4 Ins

TMAA-4-01 Remote Cable Parts
219-02918-00 Cbl Rmt Ctrl Hd Kit, comprising:
240-02158-00 Conn Shld RJ45 Shortbody Plg
360-02022-00 Grommet Mic TMA

Grid Reference List
Ref.

PCB

Circuit

Ref.

PCB

Circuit

Ref.

PCB

Circuit

J3
K4
J4
J4
L4
M5
N5
M2
M2
P4
L3
L3
M3
M3
L3
L3
K3
K3
M2
L4
L2
L2
K1
K1
J2
F2
G3
F3
E2
G2
G2
E3
E2
G2
E2
F2
E2
E3
G3
F4
G4
F4
F4

1E3
1E3
1E3
1E3
1F4
1G2
1F3
1G4
1G4
1D8
1G10
1G10
1G8
1G8
1G5
1G6
1F7
1F7
1G9
1F6
1C3
1B2
1C5
1C4
1C5
1C6
1C7
1C7
1C6
1C6
1B6
1B6
1B6
1A6
1D6
1D7
1D7
1B8
1A8
1B9
1B9
1B9
1B9

D104
D110
D201
D211
D300
D301
D720
D730
D731
E100
E101
E102
E103
E105
E710
E711
E730
E731

K5
L5
K5
K5
N5
M5
G1
F3
G3
J5
H5
K4
K4
H5
F2
F2
E4
G4

1E5
1F3
1E8
1C9
1G3
1G2
1D2
1B7
1B7
1E2
1E2
1F3
1E4
1F2
1D7
1D7
1B8
1B8

J100
J200
J201

H4
P3
B4

1E1
1E10
1C10

L712
L730
L731

D2
E4
G4

1D8
1B9
1B9

U300
U310
U400
U500
U600
U610
U611
U700

P5
N2
L3
L4
L2
K2
K2
F3

1G3
1G4
1F6 1G9 1G7
1F7
1B2
1B4
1A3
1B7

1E4 1F4
1F4 1E4
1F4 1E4
1E5 1F5

1A4
1A5
1D4
1D2
1D3
1F2
1F3
1F8
1E8
1E8
1D9
1C9
1C9
1G3
1G3
1E8
1E8
1G10
1G10
1G8
1G7

1G7
1G6
1G6
1F7
1G9
1G9
1E5
1D5
1D5
1E7
1F6
1F5
1B1
1B2
1C1
1C1
1B1
1B3
1B3
1B3
1B3
1B4
1B5
1C4
1D4
1B6
1D6
1D1
1D2
1D2
1B7
1A7

K3
K4
K4
K4

D3
M3
K1
F1
G2
J3
L4
N4
R3
R2
C3
B3
B4
N5
N5
N4
M4
L3
L3
M3
M3

L4
L3
L3
K3
M2
M2
K3
K3
J3
M4
K4
K4
L2
L2
L1
L2
L2
L2
M2
M2
M2
M2
J2
K1
K1
E3
F2
F1
F1
G1
E3
G3

D100
D101
D102
D103

MT800
MT801
Q610
Q720
Q721
R100
R110
R200
R201
R202
R210
R211
R212
R300
R301
R320
R321
R401
R402
R410
R411

R412
R420
R421
R422
R430
R431
R440
R441
R442
R501
R510
R511
R600
R601
R602
R603
R604
R605
R606
R607
R608
R609
R610
R611
R612
R701
R710
R720
R721
R722
R730
R731

Installing an Enhanced Remote Kit

471

Board Layout

IPN 220-01721-02

472

Installing an Enhanced Remote Kit

Circuit Diagram

Installing an Enhanced Remote Kit

473

23.4.2

TMAC34-0T Torso Interface (PCB IPN 220-01720-01)

Parts List
Ref.

IPN

Description

Ref.

IPN

Description

C1
C2
C3
C4
C7
C9
C10
C13
C101
C102
C103
C203
C207
C209
C213

018-16100-00
015-07470-10
015-06470-01
018-13100-00
015-27100-08
018-13100-00
018-16100-00
018-16100-00
018-16100-00
015-07470-10
015-07470-10
018-13270-00
018-13270-00
018-13270-00
018-13270-00

Cap 0603 100n 16v x7r + - 10%
Cap Cer 1206 4u7 X7r 16v
Cap Cer 1206 470n X7r 20% 50v
Cap 0603 100p 50v NPO ±5%
Cap Cer 0805 X7R 1uF 16V 10%
Cap 0603 100p 50v NPO ±5%
Cap 0603 100n 16v x7r + - 10%
Cap 0603 100n 16v x7r + - 10%
Cap 0603 100n 16v x7r + - 10%
Cap Cer 1206 4u7 X7r 16v
Cap Cer 1206 4u7 X7r 16v
Cap 0603 270p 50v NPO±5%
Cap 0603 270p 50v NPO±5%
Cap 0603 270p 50v NPO±5%
Cap 0603 270p 50v NPO±5%

R12
R13
R14
R16
R18
R19
R30
R31
R103
R104
R203
R207
R209
R213
R911

038-16100-00
038-16100-00
036-13560-00
038-15100-00
038-13220-00
038-14120-00
038-13390-00
038-13390-00
038-12100-00
038-15100-00
038-13100-00
038-13100-00
038-13100-00
038-13100-00
036-00000-00

Res 0603 100k 1/16w +-5%
Res 0603 100k 1/16w +-5%
Res M/F SMD 0805 560e 5%
Res 0603 10k 1/16w +-5%
Res 0603 220e 1/16w +-5%
Res 0603 1k2 1/16w +-5%
Res 0603 390e 1/16w +-5%
Res 0603 390e 1/16w +-5%
Res 0603 10e 1/16W ± 5%
Res 0603 10k 1/16w +-5%
Res 0603 100e 1/16w ± 5%
Res 0603 100e 1/16w ± 5%
Res 0603 100e 1/16w ± 5%
Res 0603 100e 1/16w ± 5%
Res 1206 0e 5% 0.125w

DS1

008-00014-73

LED Hp Grn Rang PCB Mtg

J1
J2
J3

240-10000-11
240-00016-00
240-00016-00

Conn SMD 18w Skt M/Match
Conn RJ45 Shld 8P8C LP RA TH
Conn RJ45 Shld 8P8C LP RA TH

U1
U2
U3

002-19120-00
002-12523-17
002-13483-00

IC TS912ID Cmos R2R Opamp
IC LM317l Reg T0252 0.5a
IC XCVR RS485 LTD SLEW RATE 3V

220-01720-01

PCB MFX Radio Remote

R1
R2
R3
R4
R6
R7
R8
R9
R10

038-13120-00
038-10000-00
038-14470-00
038-14470-00
038-15220-00
038-15100-00
038-15820-00
038-13100-00
038-15100-00

Res 0603 120e 1/16w ± 5%
Res 0603 Zero 0hm 1/16w ± 5%
Res 0603 4k7 1/16w +-5%
Res 0603 4k7 1/16w +-5%
Res 0603 22k 1/16w +-5%
Res 0603 10k 1/16w +-5%
Res 0603 82k 1/16w +-5%
Res 0603 100e 1/16w ± 5%
Res 0603 10k 1/16w +-5%

219-02882-00
302-10063-00
302-50002-00
316-06843-00
346-10030-08
349-02062-00
365-01762-00

Loom Control Head TMA
Brkt PCB Remote TM8200 Body
Bung RJ45 MFO
Pnl Frt Remote TM8200 MF0
Scrw P/T Wn1412 Kc30x08 Zbc
Scrw M3*8 T/T P/T ContiR
Lbl TM8200 Branding Bullet

Grid Reference List
Ref.

PCB

Circuit

Ref.

PCB

Circuit

Ref.

PCB

Circuit

C1
C10
C101
C102
C103
C13
C2
C203
C207
C209
C213
C3
C4
C7
C9

J2
M2
J1
D1
E2
M2
K1
J2
J2
H2
H2
D2
J1
J2
K2

1E2
1E6
1A4
1A3
1C4
1D6
1E1
1D4
1C5
1C3
1C3
1B2
1D3
1E4
1D5

1A1
1A1
1B1
1B1

TP2

1A5

U1
U2
U3

K1
D2
F2

1E5 1E3 1A4
1B2
1B4

1A4

J1
J2
J3

H2
L2
N2

1C1
1D7
1C7

MT1

1B5

R1
R10

R1
K2

1C5
1D5

1C4
1C3
1E6
1D6
1A4
1C3
1B3
1A3
1B5
1D3
1C5
1C3
1C3
1E2
1B6
1C6
1E2
1E2
1C3
1D3
1D4
1C5
1B5
1B7
1B7
1C2

F2
E2
C2
C2

G2
G2
M2
M2
F2
H2
D2
E2
R1
J2
J2
H2
H2
J1
F2
E2
J1
J1
G2
J1
M2
F2
E2
N2
N2
H2

R920
R921
R930
R932

DS1

R103
R104
R12
R13
R14
R16
R18
R19
R2
R203
R207
R209
R213
R3
R30
R31
R4
R6
R7
R8
R9
R900
R901
R910
R911
R912

474

Installing an Enhanced Remote Kit

Board Layout

IPN 220-01720-01

Installing an Enhanced Remote Kit

475

Circuit Diagram

476

Installing an Enhanced Remote Kit

TOPA-SV-024 Test Unit
The TOPA-SV-024 test unit is used to test and maintain Tait portable
and mobile radios by providing an interface between the radio, a test
PC, and an RF communications test set.
The diagram below shows the front panel of the test unit.
Figure 24.1

24.1

TOPA-SV-024 test unit

Test Setup
The diagram on the following page shows how the test unit is connected
to the radio, the test PC, and the RF communications test set.
Note

The test unit can also be connected to a Tait Orca portable
radio (TOP) using the TOPA-SV-007 cable, or to a T2000
radio using the T2000-11 cable. Use with Tait Orca and
T2000 radios is not described in this document.

TOPA-SV-024 Test Unit

477

Figure 24.2

Test setup

Test PC

serial port
(DB9)
RF comms set

T950-001
USB1.1 to serial
DB9 adapter
(optional)

TOPA-SV-024

computer
connector
(RJ12)

TPA-SV-006
cable

RF in/out
(N-type)

transmit audio
connector (BNC)

AUDIO
OUT
(BNC)

AUDIO
IN HI
(BNC)

audio
monitor
out (BNC)

receive audio /
SINAD connector
(BNC)
radio connector
(DB15)
speaker
connector

Oscilloscope
TMAA21-01 cable

microphone
connector (RJ45)

AC input
(BNC)

TOPA-SV-006 cable
(to RF in/out of
RF comms set)

TM9100 radio

power
connector

auxiliary
connector
(DB15)

TMAA23-02 cable
(50W/40W radios)
TMAA20-03 cable
(25W radios)

antenna
connector (SMA)
RF connector
(mini UHF or
BNC)

TP9100
radio

TPA-SV-011 cable
(to radio connector
of test unit)

DC power supply

TPA-SV-005
battery eliminator
(to DC power supply)
banana plugs

478

TOPA-SV-024 Test Unit

24.2

Operation
This section explains the function of the TOPA-SV-024 test unit
controls. The procedure for using the test unit is described in the relevant
section on test equipment setup.

24.2.1

Portable / Mobile Switch
This 2-way toggle switch is used to switch attenuation resistors (R4, R5,
R6) in and out of the line from the radio’s positive speaker output to the
positive receive audio/SINAD output of the test unit (before the isolating
transformer).
■

When set to Portable, the attenuation resistors are switched out.

■

When set to Mobile, the attenuation resistors are switched in
(attenuation 10:1).

Important

24.2.2

Selecting the wrong switch position may result in
incorrect SINAD readings and damage to the test unit.

Mod Audio/Audio Tap In / Off / Mic Audio Switch
This 3-way toggle switch is used to switch between Mod Audio/Audio
Tap In, Mic Audio, and Off (no audio signal).

24.2.3

■

With the Tait Orca portables, this switch can be used for setting up
dual point modulation by applying modulation to different parts of
the radio.

■

For normal transmit deviation tests (other portables and mobiles), this
switch is set to Mic Audio.

On Hook / Off Hook Switch
Important

When using the test unit with portables, the On Hook /
Off Hook toggle switch must be set to Off Hook.
Portables do not have a hookswitch, and if the switch is
set to On Hook, the accessory function key of the
portable is activated.

This 2-way toggle switch is used to simulate the microphone hookswitch
opening (“hook off”) and closing (“hook on”). This is done by
switching a 12kΩ resistor (R3) in or out of the MIC_PTT line.
■

When set to Off Hook, the 12kΩ resistor (R3) is switched out of the
MIC_PTT line. This simulates the microphone being removed from
the microphone clip.

■

When set to On Hook, a 12kΩ resistor (R3) is switched into the
MIC_PTT line. This simulates the microphone being placed on the
microphone clip.

TOPA-SV-024 Test Unit

479

24.2.4

Rx / Tx/PTT Switch
This 2-way toggle switch is used to switch between receive and transmit
mode.

24.2.5

■

When set to Rx, the PTT line is switched to high impedance.

■

When set to Tx/PTT, the PTT line is pulled to ground.

Speaker / Radio / Load Switch
This 3-way toggle switch is used during receive audio tests to switch the
audio to the test unit speaker (Speaker), to the radio’s internal speaker
(Radio) or to a dummy load consisting of R1 and R2 (Load).
Note

This switch does not disconnect the radio’s internal speaker on
mobiles. If the switch is set to Speaker or Load, this simulates
an external speaker being connected in parallel to the radio’s
internal speaker.

With all settings, a low level audio signal is available for testing
through the SINAD port.
Portable

Mobile

480

■

When set to Speaker, only the speaker of the test unit is active.

■

When set to Radio, only the speaker of the portable is active.

■

When set to Load, no speaker is active. The audio signal is terminated
in the test unit dummy load.

■

When set to Speaker, the speakers of the test unit and the mobile are
both active. The speaker of the mobile cannot be disconnected.

■

When set to Radio, only the speaker of the mobile is active.

■

When set to Load, the speaker of the mobile remains active.

TOPA-SV-024 Test Unit

24.3

PCB Information (PCB IPN 220-01418-02A)

24.3.1

Parts List (Rev. 4)

Ref.

IPN

Description

Ref.

IPN

Description

BNC1
BNC2
C1
C2
C3
C4
PL1
PL2
R1
R2
R3
R4
R5
R6
R7

240-02100-11
240-02100-11
011-54100-01
011-54100-01
020-59100-06
011-54100-01
240-00010-55
240-04021-60
032-31820-01
032-31820-01
030-55120-20
030-53560-20
030-54270-20
030-52560-20
030-55100-20

Skt Coax BNC 3.5mm Pnl N/Tag
Skt Coax BNC 3.5mm Pnl N/Tag
Cap Cer AI 1n 10% T/C B 50v
Cap Cer AI 1n 10% T/C B 50v
Cap Elec Rdl 100m 16v 6.3x11
Cap Cer AI 1n 10% T/C B 50v
Plg 15w Drng W-Wrap Pnl Mtg
Skt 6w Modr Ph Vrt T-Ent
Res M/F Pwr 17x5 8e2 5% 2.5w
Res M/F Pwr 17x5 8e2 5% 2.5w
Res Flm 4x1.6 12k 5% 0.4w
Res Flm 4x1.6 560e 5% 0.4w
Res Flm 4x1.6 2k7 5% 0.4w
Res Flm 4x1.6 56e 5% 0.4w
Res Flm 4x1.6 10k 5% 0.4w

SW1
SW2
SW3
SW4
SW5
TRAN

230-00010-42
230-00010-57
230-00010-03
230-00010-16
230-00010-03
054-00010-17

Sw Tgl On Off On Dpdt Ms500hb
Sw Tgl Dpdt On-On Pnl Mtg
Sw Tgl Spst Mini Pnl Mtg
Sw Tgr Spst 3-Pos Pnl Mtg
Sw Tgl Spst Mini Pnl Mtg
Xfmr Line 600 Ohm 1:1

Not part of the PCB:
SPKR
032-31820-01
250-00010-19

Res M/F Pwr 17x5 8e2 5% 2.5w
Spkr C/W Rubber Sealing Ring

24.3.2

PCB Layout

top side

bottom side

TOPA-SV-024 Test Unit

481

482

TOPA-SV-024 Test Unit

Portable
Mobile

Portable

Mobile

Portable
Mobile

Portable

Portable
Mobile

Portable

Mobile

Portable

Portable
Mobile

Portable

Mobile

not fitted

MOD AUDIO / AUDIO TAP IN

not fitted

RADIO

The component values in the schematic diagram are
indicative only. Refer to the parts list for actual values
used.

not fitted

SHOULD BE DPTT

SPKR 8.2 Ω
IPN 032-31820-01

not part of PCB

SPEAKER 4Ω
IPN 250-00010-19

24.3.3
Circuit Diagram

Tait General Software Licence Agreement
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you (the “Licensee”) and Tait Electronics
Limited (“Tait”). By using any of the Software
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483

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Mod Date                        : 2005:08:03 17:28:04+12:00
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Title                           : MMA-00017-01.book
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MMA 00017 01 Tx9000/TM9000 TP9000/TM9000 Service Manual/TM9100 Manual TM9100

Tx9000/TM9000 -TP9000/TM9000 Service Manual/TM9100 Service Manual TM9100 Service Manual

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