Crescend Technologies VB0001 Continuous Duty Power Amplifier User Manual h100

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INSTALLATION & SERVICE
MANUAL
MODEL H100
CONTINUOUS DUTY
POWER AMPLIFIER
450-470 MHz
May 17, 2000
Crescend Technologies
2255 Lois Drive, Suite 1
Rolling Meadows, IL 60008
Tel:
847 593 1213
Fax:
847 593 1320
Web Site: www.crescendtech.com
TABLE OF CONTENTS
Par.
No.
Section 1
General Description
Page
No.
1-1
Introduction
1-2
General Description
1-3
Functional and Physical Specifications
1-4
Equipment Changes
1-5
Ordering Information
Section 2
Installation
2-1
Introduction
2-2
Electrical Service Recommendations
2-3
Unpacking and Inspection
2-4
Installation Instructions
2-5
Amplifier Module Alarm and Control
Connector
Section 3
Operating Instructions
3-1
3-2
3-3
3-4
Introduction
Location and Function of Amplifier
Module Control and Indicators
Initial Start-Up and Operating
Procedures
Variable Input Switch
Section 4
Principles of Operation
4-1
Introduction
10
4-2
RF Input Signal
10
4-3
RF Output Load
10
4-4
Functional Description
10
4-5
H100 Amplifier Module
10
4-5.1
Main Amplifier
10
4-5.2
Loop Control
11
4-5.3
Amplifier Monitoring
11
4-5.4
Amplifier Module Cooling
11
4-6
Power Distribution
11
Rev 1.
TABLE OF CONTENTS (Continued)
Section 5
Maintenance
5-1
Introduction
12
5-2
Periodic Maintenance
12
5-3
Test Equipment Required for Test
5-4
Cleaning air Inlets/Outlets
12
13
5-5
Performance Test
13
5-5.1
Amplifier Performance Test
13
5-6
Field Replaceable Parts and Modules
14
5-6.1
H100 Power Amplifier Module
14
5-6.2
Cooling Fans
14
5-6.3
Fuse
15
Section 6
Troubleshooting
6-1
Introduction
16
6-2
Troubleshooting
16
6-3
Return for Service Procedure
16
6-3.1
Obtaining an RMA
16
6-3.2
Repackaging for Shipment
16
Figure
LIST OF ILLUSTRATIONS
Page
4-1
Variable Input Switch
10
4-2
H100 Block Diagram
11
5-1
Amplifier Test Setup diagram
15
LIST OF TABLES
Table Page
1-1
Major Amplifier Components
1-2
H100 Amplifier Functional Specifications
1-3
Load Mismatch Tolerance
3-1
Amplifier Module Alarm and Control
Connections
H100 Amplifier Module Control and Indicators
5-1
Periodic Maintenance
12
5-2
Test Equipment Required
12
6-1
Troubleshooting
16
2-1
Rev 1.
1.
GENERAL DESCRIPTION
1.1.
INTRODUCTION
This manual contains information and procedures for installation, operation, of Crescend’s H100
Continuous Duty Power Amplifier. The manual is organized into five sections as follows:
Section 1.
General Description
Section 2.
Installation
Section 3.
Operating Instructions
Section 4.
Principles of Operation
Section 5.
Maintenance
Section 6:
Troubleshooting
1.2.
GENERAL DESCRIPTION
The H100amplifier is designed for trunking and conventional repeater applications requiring high duty
cycles. The H100 amplifier operates from RF power sources of 250 milliwatts up to 25 watts. The
amplifier consists of an input attenuator, a predriver amplifier, a microprocessor circuit control, and two
stages of amplification followed by a 7-pole distributed low-pass filter and associated control circuitry.
The H100 amplifier has a microprocessor control board that maintains a constant output power under
varying signal input and output load conditions. A system functional block diagram of the Model H100
amplifier is contained in section 4 of this manual.
1.3.
FUNCTIONAL AND PHYSICAL SPECIFICATIONS
Functional and physical specifications for the H100 amplifier are listed in tables 1-2 and 1-3.
1.4.
EQUIPMENT CHANGES
Crescend Technologies, Inc. reserves the right to make minor changes without notice, including but
not necessarily limited to component substitution and circuitry changes. Such changes may or may not
be incorporated in this manual, although it is our intention to keep each manual as up-to-date as
possible. To that end, we ask that you, our customer, share with us information acquired in field
situations which might be of assistance to another user. If you share it with us, we’ll pass it around.
1.5.
ORDERING INFORMATION
Table 1-1 following gives the part numbers and descriptions to be used when ordering either an entire
amplifier or replacement fans.
Table 1-1. Major Amplifier Components
Rev 1.
MODEL NUMBER
DESCRIPTION
H100
250 mW – 25 W 450-470 MHz Amplifier
800-00889-001
Fan Assembly
Table 1-2. H100 Amplifier Functional Specifications
Frequency Range:
450-470 MHz.
Operating Voltage:
+28 Vdc (±1.0 Vdc)
Current Draw
9 Amperes Typical; 11 Amperes Maximum
Duty Cycle:
100%
Power Input:
250 mW - 25 W.
Power Output:
100 Watts
Spurious & Harmonics.
-70 dBc (Minimum)
Input/Output Impedance
50 ohms (Nominal)
Load VSWR Tolerance
See Chart
Input/Output Connector:
Type N Female
Vertical Mounting:
10.47”
Horizontal Mounting:
3.38’
Depth.
17.0”
Weight:
20 Pounds Nominal
Cooling Method:
Fan Forced Air Over Heatsink
Operating Temp. Range:
0 °C. to +60 °C.
Storage & Transport:
-10 °C. to +70 °C.
Humidity:
80% at +40 “C. (Non condensing)
Altitude:
10,000 Feet Maximum
OPTIONS
INDICATORS
DC PWR ON, LOW OUTPUT, LOW INPUT,
HIGH INPUT, HIGH VSWR, OVER TEMP.,
L.E.D. POWER BAR METER
Remote Control/Display Panel
CONTROLS
PWR CONTROL (-10 dB)
NOTES:
Manufacturer’s Rated Output Power of this Equipment is for Single Carrier
Operation.
All specifications apply at +28 Vdc operating voltage.
Table 1-3. Load Mismatch Tolerance
Rev 1.
Full Power, Sustained Operation
2:1 Maximum
Sustained Operation at Reduced Power
3:1
Microprocessor Shutdown
10:1
2.
INSTALLATION
2.1.
INTRODUCTION
This section contains installation recommendations, unpacking, inspection, and installation instructions
for the H100 amplifier. Carefully read all material in this section prior to equipment unpacking or
installation. Also read and review the operating procedures in Section 3 prior to installing the
equipment. It is important that the licensee perform these tasks correctly and in good faith. If applicable,
carefully read Parts 73 and 74 of the Federal Communications Commission (FCC) rules to determine
how they apply to your installation. DON’T TAKE CHANCES WITH YOUR LICENSE.
2.2.
ELECTRICAL SERVICE RECOMMENDATIONS
Crescend Technologies recommends that proper AC line conditioning and surge suppression be
provided on the primary AC input to the +28 Vdc power source. All electrical service should be installed
in accordance with the National Electrical Code, any applicable state or local codes, and good
engineering practice. Special consideration should be given to lightning protection of all systems in view
of the vulnerability of most transmitter sites to lightning. Lightning arrestors are recommended in the
service entrance. Straight, short ground runs are recommended. The electrical service must be well
grounded.
Each amplifier system should have its own circuit breaker, so a failure in one does not shut off the
whole installation. Circuit breakers should be thermal type, capable of handling an inrush current of 90
Amps, in a load center with a master switch.
2.3.
UNPACKING AND INSPECTION
This equipment has been operated, tested and calibrated at the factory. Only in the event of severe
shocks or other mistreatment should any substantial readjustment be required. Carefully open the
container(s) and remove the amplifier module(s). Retain all packing material that can be reassembled in
the event that the unit must be returned to the factory.
CAUTION:
Exercise care in handling equipment during inspection to prevent damage
caused by rough or careless handling.
Visually inspect the amplifier module for damage that may have occurred during shipment. Check for
evidence of water damage, bent or warped chassis, loose screws or nuts, or extraneous packing
material in the connector or fans. Inspect the rear panel connector for bent connector pins. If the
equipment is damaged, a claim should be filed with the carrier once the extent of any damage is
assessed. We cannot stress too strongly the importance of IMMEDIATE careful inspection of the
equipment and the subsequent IMMEDIATE filing of the necessary claims against the carrier if
necessary. If possible, inspect the equipment in the presence of the delivery person. If the equipment is
damaged, the carrier is your first area of recourse. If the equipment is damaged and must be returned
to the factory, write or phone for a return authorization. Crescend may not accept returns without a
return authorization. Claims for loss or damage may not be withheld from any payment to Crescend,
nor may any payment due be withheld pending the outcome thereof. WE CANNOT GUARANTEE THE
FREIGHT CARRIER’S PERFORMANCE.
2.4.
INSTALLATION INSTRUCTIONS
The H100 amplifier module is designed for installation in a sub rack that permits access to the rear of
the sub rack for connection of DC power, RF, and monitor cables.
To install the amplifier proceed as follows:
1. Install sub rack in equipment rack and secure in place.
2. Install the plug-in H100 amplifier module(s) in the sub rack. Tighten top and bottom thumbscrews.
3. Connect 50-ohm antenna cable to RE OUT connector on rear of amplifier module.
Rev 1.
4. Connect the transceiver/exciter output to RF IN connector on rear of amplifier module.
5. Connect alarm and control cable to 9-pin D-sub connector on rear of amplifier module. Refer to
paragraph 2-5 for connector definition.
WARNING: Turn off external primary DC power before connecting DC power cables.
6. Connect positive primary power to +28V terminal and negative primary power to GND terminal on
rear of amplifier module. Tighten the power connections.
7. Check your work before applying DC voltage to the system. Make certain all connections are tight
and correct.
8. Measure primary DC input voltage. DC input voltage should be +28 Vdc ti .0 Vdc. If the DC input
voltage is above or below the limits, call and consult Crescend before you turn on your amplifier
system.
9. Refer to section 3 for initial turn -on and checkout procedures.
2.5.
AMPLIFIER MODULE ALARM AND CONTROL CONNECTOR
The alarm and control connections on the amplifier are made through a female 9-pin D-sub connector
and are listed and described in table 2-1.
Table 2-1. Alarm and Control Connector Pins (on Rear of H100 Module)
PIN NUMBER FUNCTION
Rev 1
DESCRIPTION
Low Input Power
GND
Indicates alarm when input drive is approximately 2.5 dB
below specified range
System Ground
Over Temperature
Indicates alarm if junction temperature exceeds 60 °C
VSWR
Indicates alarm for VSWR >3:1
Fwd Detect Vdc
Input drive range set
External Reset
Resets microprocessor after alarm condition is set
DC Power
RF Output Status
Indicates alarm condition when 24 Vdc > power supply > 30
Vdc
Indicates alarm if an output transistor fails
Not used
No connection
3.
OPERATING INSTRUCTIONS
3.1.
INTRODUCTION
This section contains operating instructions for the H100 Amplifier.
3.2.
LOCATION AND FUNCTION OF AMPLIFIER MODULE CONTROL AND
INDICATORS.
The location and function of the H100 amplifier module control and indicators is described
in detail in table 3-1.
Table 3-1. H100 Amplifier Module Control and Indicators
NO
NAME
DC PWR ON
Indicator
LOW OUTPUT
Indicator
LOW INPUT
Indicator
HIGH INPUT
indicator
HIGH VSWR
Indicator
OVER TEMP
Indicator
PWR CONTROL
Adjustment
POWER
Indicator
3.3.
FUNCTION
Green LED. Continuous illumination at voltages from 26-29.9 Vdc
(this is the acceptable operating range for the H100 amplifier). At
DC voltages from 24-25.9 Vdc, the LED will flash and the output
power will remain at its specified level. At voltages less than 24 and
greater than 30 Vdc, the H100 will shut down, and the DC POWER
ON LED will flash.
Red LED. Activates when.
1. The op amp in the automatic gain control becomes saturated at
its rails, or
2. One of the finals in the amplifier becomes faulty.
Red LED. Activates when input drive to the H100 drops by 1.5 dB
from its rated input drive. At this point, the led will flash, but the
output will remain at its rated power. Should the RF input drive
drop by another 1 dB, the LED will illuminate continuously and
there will be no output from the H100 amplifier.
Red LED. Activates when input drive to the H100 is increased by
1.5 dB from its rated input drive. At this point, the led will flash, but
the output will remain at its rated power. Should the RF input drive
increase by another 1 dB, the LED will illuminate continuously and
there will be no output from the H100 amplifier
Red LED. Activates at loads greater than 3:1. At this point, the
amplifier output will drop by -3dB. Should the output load open (VS
WR
>10:1) The indicator will still be lit and there will be no output from
the amplifier.
Red LED. Activates when the heatsink of the amplifier exceed 63
degrees Celsius. At this point, the H100 amplifier will shut down,
and there will be no output. When the amplifier has sufficiently
cooled, the H100 will resume normal operation.
Allows user to reduce the power output by more than 10 dB below
the factory-set 100 watts.
Output LED bar level indicator. Each bar represents 10 watts of
output power.
Initial Startup
To perform the initial start-up, proceed as follows:
Double-check to ensure that all input and output cables are properly connected.
Rev 1
CAUTION:
Before applying power, make sure that the input and output of the
amplifier are properly terminated at 50 ohms. Do not operate the
amplifier without a load attached. Refer to table 1 -2 for input power
requirements. Excessive input power may damage the amplifier.
NOTE:
The output coaxial cable between the amplifier and the antenna
must be 50-ohm coaxial cable. Use of any other cable will distort the
output.
2. Verify that power supply measures 28 ±1 Vdc. Apply power to the amplifier(s). Do not
apply a RF signal to the amplifier system.
3. Visually check the indicators on each amplifier module, and verify the following:
a.
The DC PWR ON indicator (green) on all amplifier modules should be on.
b.
The LOW INPUT indicator (red) on all amplifier modules should be on.
4. Turn on external exciter/transceiver and apply RF input signals. All red LEDs should turn
off within 2 5 seconds.
3.4.
VARIABLE INPUT SWITCH
If the RF input to the H100 amplifier should change, figure 4-1 shows which DIP switch to
activate for various inputs. A trained technician, with prior approval and instructions from
Crescend’s service department, should only perform this. Failure to receive prior permission
to open the amplifier could void the warranty.
1. Verify that no DC or RF is applied to the H100.
2. If necessary, remove H100 from sub rack.
3. Remove the lid from the H100.
4. Locate the variable toggle switch (S1) on the 500 -00800-001 driver PCB.
5. Refer to figure 4-1 for various switch settings.
Rev. 1
4.
PRINCIPLES OF OPERATION
4.1.
INTRODUCTION
This section contains a functional description of the H100 Amplifier.
4.2.
RF INPUT SIGNAL
H100 amplifiers are equipped with an input variable switch that ranges from 250m W to 25W
(see figure 4-1). They have a predriver module that consists of an input attenuator pad,
variable input attenuator, and a power amplifier module that provides up to 13dB of gain.
The microprocessor uses detector circuitry to maintain a constant output level by sensing RF
input, output, VSWR, temperature, and driver/final failures. Input VSWR to the H100 should
not exceed 2:1 for best performance.
Input Power Range 1: 0.25 – 0.5 watts
Input Power Range 2: 0.5- 1.0 watts
Input Power Range 3: 1-2 watts
Input Power Range 4: 2- 4 watts
Input Power Range 5: 4 8 watts
Input Power Range 6: 8 16 watts
Input Power Range 7: 16 25 watts
Input Power Range 8: Not Used
Figure 4-1. Variable Input Switch
4.3.
RF OUTPUT LOAD
The load impedance should be as good as possible (2:1 or better) in the working band for
good power transfer to the load.
4.4.
FUNCTIONAL DESCRIPTION
The H100 amplifier (see block diagram figure 4-2) is a linear, single channel amplifier that
operates in the frequency band from 450 MHz to 470 MHz. The amplifier specifications are
listed in table 1-2. Each amplifier is a self-contained plug-in module and is functionally
independent of other amplifier modules. The amplifier modules are designed for parallel
operation to achieve high peak power output, and for redundancy in unmanned remote
locations. Each amplifier in the system can simultaneously transmit carrier frequencies, at an
average total power output of 100 watts.
Figure 4-2. H100 Block Diagram
4.5.
H100 AMPLIFIER MODULE
The amplifier module has an output of 100 watts power with all harmonics suppressed to better than Rev. 1
10
70 dBc below carrier level. The amplifier module is comprised of:
Microprocessor board/alarm monitoring
Pre-driver board/splitter
Two final gain stages
Alarm monitoring, control, and display panel
Distributed low pass filter board/ combiner board
4.5.1.
MAIN AMPLIFIER
The input and output of the amplifier employ three -stage, class AB amplifiers which provide
approximately 54 dB of gain in the 20 MHz frequency band from 450 MHz to 470 MHz The amplifier
operates on +28 Vdc, and a bias voltage of +6 Vdc, and is mounted directly on a heat sink. The alarm
logic controls the +6 Vdc bias voltage that shuts down the amplifier.
4.5.2.
LOOP CONTROL
The loop control circuitry consists of a microprocessor (see paragraph 4-2), which prevents the RF
output and input power from exceeding the safe operating maximum power levels.
The RF output power from the model H100 amplifier is controlled by the microprocessor. A coupled
detector on the low-pass filter PCB monitors the final RF output level and generates a DC voltage
(VFWD) proportional to the RF output level. VF WD is fed back to the microprocessor. The
microprocessor compares this voltage to a reference voltage, and varies the output gain of the driver
module to maintain a constant 100-watt output. The microprocessor also provides over-temperature
protection for the amplifier. All RE modules in the amplifier are mounted on a common heatsink. The
modules all have temperature-sensing ICs mounted on them, which constantly monitor heat and
convert it to a DC voltage. This voltage is sent to the microprocessor which shuts down the amplifier
should temperatures exceed 63 degrees Celsius. When the amplifier has sufficiently cooled down, the
microprocessor re-enables the amplifier.
The output of the driver amplifier, approximately five watts of power, is fed to a 2-way power splitter,
amplified by the two parallel final amplifier modules, then combined and fed to the 7 -pole distributed
low-pass filter. The filter attenuates any spurious and harmonic signals that may have been produced
by the various gain stages, for a final RE output of 100 watts. Double-shielded Teflon cable is used for
all high power RF interconnections.
4.5.3.
AMPLIFIER MONITORING
In the main amplifier modules, all normal variations are automatically compensated for by the
microprocessor. However, when large variations occur beyond the adjustment range of the loop control,
a low output alarm will occur. The alarms are displayed in the front panel indicators.
Status indicators on the front panel include DC PWR ON, LOW OUTPUT, LOW INPUT, HIGH INPUT,
HIGH VSWR, and OVER-TEMP. AN RF power-level adjustment potentiometer is also provided on the
front panel. The power adjustment allows the user to reduce the power output by more than 10 dB
below the factory-set 100-watt output. An output LED bar level indicator is also provided on the H100.
Each bar represents 10 watts of output power.
4.5.4.
AMPLIFIER MODULE COOLING
Although each amplifier module contains its own heat sink, it is cooled with forced air. Two fans are
used for forced air-cooling and redundancy. The fans located on the rear of the amplifier module and
operating continuous duty from applied DC, draw ambient air in through the front of the amplifier and
exhaust hot air out the rear of the module. The fans are field replaceable
4.6.
POWER DISTRIBUTION
Primary DC power for the system is provided by the host system. This system supplies each amplifier
module with +28 Vdc directly via a 15-amp fuse located on the rear panel of the amplifier. The amplifier
module has a DC/DC converter that converts the +28 Vdc to +6 Vdc to provide bias.
Rev. 1
11
5.
MAINTENANCE
5.1.
INTRODUCTION
This section contains periodic maintenance and performance test procedures for the Kb. It also
contains a list of test equipment required to perform the identified tasks.
NOTE:
Check your sales order and equipment warranty before attempting to service or repair the
unit. Do not break the seals on equipment under warranty or the warranty will be null and
void. Do not return equipment for warranty or repair service until proper shipping
instructions are received from the factory.
5.2.
PERIODIC MAINTENANCE
Periodic maintenance requirements are listed in Table 5-1. Table 5-1 also lists the intervals at which the
tasks should be performed.
WARNING: Wear proper eye protection to avoid eye injury when using compressed air.
Table 5-1. Periodic Maintenance
TASK
Cleaning Air Vents
INTERVAL
30 Days
ACTION
Inspect and clean per paragraph 5-4
Inspection Cables and
Connectors
12 Months
Performance Tests
12 Months
Inspect signal and power cables for
frayed insulation. Check RF connectors to
be sure that they are tight.
Perform annual test per paragraph 5-5.
5.3.
TEST EQUIPMENT REQUIRED FOR TEST
Test equipment required to test the amplifier system is listed in Table 5-2. Equivalent test equipment
may be substituted for any item.
NOTE:
All RF test equipment must be calibrated to 0.05 dB resolution. Any deviation from the
nominal attenuation must be accounted for and factored into all output readings.
Table 5-2. Test Equipment Required
NOMENCLATURE
MANUFACTURER
MODEL
Signal Generator
H.P.
8648B
40 dB Attenuator, 250 Watt
Tenuline
DC power supply
H.P
6269B
Spectrum Analyzer
H.P.
8560E
Dual Directional Coupler
Narda
Power Meter / Sensor
H.P.
437B I 8481A
Fluke
73
Linear Discreet Amplifier
Digital Multi-Meter
Current Probe
Rev. 1
12
5.4.
CLEANING AIR INLETS/OUTLETS
The air inlets and outlets should be cleaned every 30 days. If the equipment is operated in a severe
dust environment, they should be cleaned more often as necessary. Turn off DC power source before
removing fans. If dust and dirt are allowed to accumulate, the cooling efficiency may be diminished.
Using either compressed air or a brush with soft bristles, loosen and remove accumulated dust and dirt
from the air inlet panels.
5.5.
PERFORMANCE TEST
Performance testing should be conducted every 12 months to ensure that the amplifier system meets
the operational specifications listed in table b -2. Also verify system performance after any amplifier
module is replaced in the field. The test equipment required to perform the testing is listed in table 5-2,
and the test setup is shown in figure 5-1.
N OTE:
The frequencies used in this test are typical for an amplifier with a band from 450 MHz
to 470 MHz.
5.5.1.
AMPLIFIER PERFORMANCE TEST.
This test is applicable to a sub rack equipped with one to five plug-in H100 amplifier modules.
Perform the tests applicable to your system. To perform the test, proceed as follows:
Connect test equipment as shown in figure 5-1.
NOTE: Do not apply any RF signals at this time.
Turn on DC (28 V). Turn on signal generator and set frequency to 860 MHz.
5.5.2.
HARMONICS TEST
With the power amplifier set at 100 watts power output, use the spectrum analyzer and check the
frequency band from 450 MHz to 470 MHz for harmonics. Harmonics should be -70 dBc maximum.
5.5.3.
SPURIOUS TEST
With the power amplifier set at 100 watts power output, use the spectrum analyzer and check the
frequency band from 450 MHz to 470 MHz for spurious signals. Spurious signals should be -70 dBc
maximum.
Rev 1.
13
Figure 5-1. Amplifier Test Setup Diagram
5.5.4.
GAIN TEST:
Disconnect spectrum analyzer from test setup, and connect the power meter.
Apply the rated input RF drive to the H100. Verify that the unit delivers 100 W out for rated input
5.6.
FIELD REPLACEABLE PARTS AND MODULES
The following parts and modules can be replaced in the field on site by a qualified technician with
experience maintaining RF power amplifiers and similar equipment:
5.6.1.
H100 POWER AMPLIFIER MODULE
To replace a H100 module, proceed as follows
1. Loosen two thumbscrews that secure amplifier module to sub rack.
CAUTION:
When removing the amplifier from the sub rack, it is very important to support
the amplifier such that the rear of the module does not suddenly drop when
the guide rail disengages from the track. A drop such as this could damage
the rear of the amplifier.
2. Use the handles on the front of the module, and with a steady even pressure, pull t he module out of
chassis.
5.6.2.
COOLING FANS
To replace a cooling fan, proceed as follows.
Rev 1.
14
1.
Remove amplifier module from sub rack.
2.
Loosen three screws that secure fan to amplifier module. Disconnect fan power connector from
amplifier module.
3.
5.6.3.
Install replacement fan in reverse order of steps I and 2 above.
FUSE
The H100 amplifier 28 Vdc power input line contains a single fuse as follows:
Manufacturer:
Littlefuse
Manufacturer’s Number:
313015
Rating:
15 amps
Style
3AG Slo-Blo
Size:
1/4 inch diameter
1-1/4 inches long
Rev 1.
15
6.
TROUBLE SHOOTING
6.1.
INTRODUCTION
This section contains a list of problems, which users have encountered, and a few suggested actions
that may correct the problem. If the suggested corrective action does not eliminate the problem, please
contact your Crescend field representative or the factory for further instructions.
NOTE: Check your sales order and equipment warranty before attempting to service or
repair the unit. Do not break the seals on equipment under warranty or the warranty will be
null and void. Do not return equipment for warranty or repair service until proper shipping
instructions are received from the factory.
6.2.
TROUBLESHOOTING
Refer to table 6-1 for troubleshooting suggestions.
Table 6-1. Troubleshooting.
SYMPTOM
Any voltage indicators (green) are not
lit or blinking
SUGGESTED ACTION
Check that subrack power connection is secure.
Check for proper power supply voltage.
Check fuses or circuit breakers on amplifier or subrack.
Verify that amplifier is fully inserted into subrack.
OVER TEMP alarm (red) is lit
Verify fan(s) are operating properly. Check ambient
temperature (not to exceed spec - see table 1-2)
HIGH/LOW INPUT alarm (red) is lit
Verify RF input level does not exceed spec - see table 1-2
HIGH VSWR alarm (red) is lit
Check output connections and cables for integrity and
tightness
LOW OUTPUT alarm (red) is lit
Contact Crescend field representative or factory.
6.3.
RETURN FOR SERVICE PROCEDURES
When returning products to Crescend, the following procedures will en sure optimum response.
6.3.1.
Obtaining an RMA
A Return Material Authorization (RMA) number must be obtained prior to returning equipment to
the factory for service. Please contact our Customer Service Department at (847) 593-1213 to
obtain this number. Failure to obtain this RMA number will result in considerable delays in
receiving repair service.
6.4.
Repackaging for Shipment
To ensure safe shipment of the amplifier, it is recommended that the package designed for the
amplifier be used. The original packaging material is reusable. If it is not available, contact
Crescend’s Customer Service Department for packing materials and information.
Rev 1.
16

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PDF Version                     : 1.2
Linearized                      : No
Creator                         : h100.doc - Microsoft Word
Create Date                     : 2000:05:18 14:56:40
Title                           : h100
Producer                        : Acrobat PDFWriter 4.0 for Windows
Modify Date                     : 2000:05:18 15:05:24-05:00
Page Count                      : 16

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