Array Solutions Array Solutions X8NOM2000 Amateur Radio Service Linear HF Amplifier User Manual OM2000
Array Solutions dba Array Solutions Amateur Radio Service Linear HF Amplifier OM2000
Contents
- 1. Users Manual OM2000+
- 2. User Manual replacement exhibit 6
Users Manual OM2000+
Exhibit 6 Page 2 from 35
TABLE OF CONTENTS
1. GENERAL INFORMATION ..................................................................... 4
2.1. Introduction …………………………………………………………………. 4
2.2. Specification …………………………………………………………………. 4
2.2.1. Parameters …………………………………………………………………. 4
2.2.2. Protection Circuits …………………………………………………………………. 4
2.2.3. Indicators …………………………………………………………………. 5
2.2.4. Features …………………………………………………………………. 5
2. SAFETY INSTRUCTIONS …………………………………………………………………. 6
3. GENERAL DESCRIPTION …………………………………………………………………. 7
3.1. HF part …………………………………………………………………. 7
3.2. Power Supply …………………………………………………………………. 8
3.3. Safety Devices …………………………………………………………………. 9
4. INSTALLATION …………………………………………………………………. 9
4.1. Grounding …………………………………………………………………. 10
4.2. Coaxial Cable …………………………………………………………………. 10
4.3. Control Cable …………………………………………………………………. 10
4.4. Main Supply …………………………………………………………………. 11
4.5. Cooling …………………………………………………………………. 11
5. OPERATION …………………………………………………………………. 12
5.1. Operation Elements …………………………………………………………………. 12
5.2. Preparation for operation ………………………………………………………………. 14
5.2.1. Display menu …………………………………………………………………. 15
5.2.2. Settings menu …………………………………………………………………. 17
5.2.3. Service menu …………………………………………………………………. 19
5.3. Operation mode …………………………………………………………………. 22
5.4. Tuning of the Power Amplifier ……………………………………………………… 24
6. MAINTENANCE …………………………………………………………………. 28
6.1. Indication of Fault Conditions ……………………………………………………… 28
Exhibit 6 Page 3 from 35
6.2. Fuse Replacement …………………………………………………………………. 31
6.3. Tube Replacement …………………………………………………………………. 31
6.4. Cleaning …………………………………………………………………. 31
7. APPENDIX …………………………………………………………………. 32
7.1. Primary AC selection …………………………………………………………………. 32
7.2. Removing the HV Transformer ……………………………………………………. 33
7.3. Block Diagram of the OM2000+ Power Amplifier ………………………… 35
Exhibit 6 Page 4 from 35
1. GENERAL INFORMATION
1.1. Introduction
he OM Power model OM2000+ is designed for all short wave amateur bands from 1.8 to 29.7 MHz
(including WARC bands) plus 50 MHZ and all modes. It is equipped with a ceramic tetrode
FU-728F.
1.2. Specification
1.2.1. Parameters
Frequency Coverage Amateur Bands 1.8 – 29.7 MHz including WARC + 50 MHz
Power Output 1500 W in SSB/CW on HF bands, 1500 W in CW/SSB on 6m
1500 W in RTTY
Input Power Usually 70W for full Output Power
Input Impedance 50 Ohm, VSWR < 1.5 : 1
Power Gain 15 dB
Output Impedance 50 Ohm unbalanced
Maximum Output SWR 2 : 1
SWR protection Automatic switching to STBY, when reflected power
is 250W or higher
Intermodulation distortion 32dB below nominal output
Suppression of harmonics < -50 dBc
Tubes FU-728F Ceramic tetrode
Cooler Centrifugal blower + Axial blower
Power supply Switchable 220V, 230V, 240V, 50/60 Hz
Transformers One toroidal transformer 3kVA
Dimensions 15,4“ x7,7” x 14,6” (width x height x depth)
Weight 24 kg / 52 lbs
1.2.2. Protection Circuits
There are several protection circuits used in the amplifier. They are activated when one or
more of next parameters exceed defined values or some unwanted occasion occurs.
VSWR too high
Anode current too high
Anode voltage error
Screen current too high
Screen voltage error
T
Exhibit 6 Page 5 from 35
Grid current too high
Grid voltage error
Heating voltage error
Mistuning of PA
Temperature to high
Soft start for fuses protection
“switch-on blocking “ at opened amplifier
1.2.3. Indicators
Number of indicators visible on the front panel will inform you about value of some parameters
or operation status:
OLED display 4 x 20 characters
Analog Wattmeter Double system meter for forward and reflected power
measuring
LED Indicators ON AIR – amplifier in transmitting mode
STBY – standby mode
FAULT – failure, switching off for abt. 4 sec
ON – ON status
1.2.4. Features
Manufacturer implemented some of the company’s current development results with most
wanted operating and safety features into this new model:
High level of protections
Antenna switch for 3 different antennas
Memory for faults and warnings, easy maintenance
Automatic set-up anode current (BIAS) – no need to adjust manually after changing
the tube
Temperature controlled 2-speed centrifugal blower ( turbine ) + axial blower
Full QSK with silent relay
Many operational parameters to display
Easy transport due to detachable HV transformer
The smallest and lightest 2000 W PA on the market
Exhibit 6 Page 6 from 35
2. SAFETY INSTRUCTIONS
WARNING!
DANGEROUS HIGH VOLTAGE INSIDE!
The power amplifier is using high voltage up to 3000V DC, which is very dangerous for human life!
Read next safety instructions carefully first, before you will start to install and operate power
amplifier! NEVER VIOLATE NEXT RULES!
WARNING!
NEVER ALLOW CHILDREN to play around PA or to touch power amplifier or connected cables in
working condition, or to push anything into the case holes!
WARNING!
Never turn the amplifier on without the upper lid in place. DO NOT ATTEMPT TO SHORT OR BYPASS
safety switch under upper lid!
WARNING!
The OM2000+ amplifier is neither to be used in a WET or HUMID environment nor to be exposed to
RAINFALL!
WARNING!
Do not turn the amplifier ON without having connected the ANTENNA or properly rated DUMMY
LOAD! A hazardous HF voltage may build up on the antenna connector after turning the amplifier on
with no antenna or dummy load connected!
WARNING!
Before opening the upper lid of the amplifier make sure that power supply has been disconnected
AT LEAST 10 minutes allowing the electrolytic capacitors to discharge fully. Disconnect power cord
from the outlet!
WARNING!
Any work inside the PA (internal fuses replacement, tube replacement, etc.) can be carried out only
by professionally qualified person!
Exhibit 6 Page 7 from 35
CAUTION
The amplifier must be installed in such a way that free flow of hot air from the tube is allowed. The
amplifier must not be installed in a constrained surrounding (i.e. tight shelves etc.). During long time
operation ventilation grid can reach high temperature. Do not touch it!
CAUTION
The amplifier must be properly grounded during operation.
CAUTION
During operation the amplifier must be installed in such a way that the rear side remains accessible.
CAUTION
The amplifier is an A category product. In a household it can influence other electric appliances. In
such cases the user is to take proper actions to mitigate this disturbance.
CAUTION
Read this manual carefully. Fallow all of instructions during installation and operation to avoid
damage to the amplifier not covered by manufacturer´s warranty! Do not attempt to perform any
change of hardware or software!
3. GENERAL DESCRIPTION
3.1. HF part
his amplifier is using a ceramic tetrode FU-728F in a grounded-cathode circuit (input into control
grids). The OM2000+ amplifier achieves excellent linearity by the voltage stabilization of the
control grid bias and the screen voltage. The power input is given to the control grids, using a
broadband input circuit with an input impedance of 50 Ohms. This adaptable input circuitry ensures a
good input SWR (better than 1.5 : 1) on all amateur bands.
T
Exhibit 6 Page 8 from 35
The output of the amplifier is a Pi-L circuit. The ceramic capacitor for TUNE and LOAD are divided. This
enables the amplifier to be tuned exactly and makes it possible to easily return to the previously set
positions after band changes.
Top view on the opened OM2000+
Tetrode FU728F Antenna Switch Blower Power Supply Board Switch-ON Board
Output Pi-L Circuit Tuning Capacitor Subpanel HV transformer
3.2. Power Supply
Power amplifier is using one 3 KVA toroidal transformer. A soft start is provided using relays and
resistors (placed on the switch-ON board). The high voltage is made by combining 4 x 530V AC (total
abt. 2950V DC) @ 1.2A. Each has its own rectifier and filter. In the high voltage circuit, safety resistors
are employed to protect the amplifier against overload (placed on the power supply board).
The separated supply for screen grid is regulated by stabilization with MOSFET and delivers abt. 330V
DC at 100mA. Control grid voltage is also stabilized (-120V DC). Change of stabilized first grid voltage
is controlled by the software (EBS for example).
Exhibit 6 Page 9 from 35
3 kVA toroidal transformer is visible on the left
side. Switch-ON board is in the front, Power
supply board behind it.
CAUTION
Primary section of the transformer is switchable for 220 - 240 VAC. Factory setting is 230VAC. If the
AC voltage in your network is 220 or 240 Volts, you need to set the correct value before first starting
of the PA. See part 7.1. for more information.
3.3. Safety Devices
Control and monitoring circuits ensure control and safety during malfunctions of the PA. These are
placed on the Control board, which is located on the chassis subpanel.
One of the important safety element is
mechanical switch for AC blocking at opened
amplifier.
4. INSTALLATION
NOTE
Read this chapter carefully prior you will start installation. Before unpacking inspect shipping carton
first, if it is not damaged. Keep all of packing parts for possible future shipment. Check unpacked power
amplifier. If you find some damaging, contact your dealer immediately to keep full warranty.
During installation go step by step according to the next parts.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Exhibit 6 Page 10 from 35
4.1. Grounding
CAUTION
The amplifier has to be grounded properly! Connect the screw on the rear panel of the amplifier to
your local grounding system with a copper cable; use a cross-section of 4 mm2 at least.
Connect your transceiver to the same grounding system of your shack carefully! Use minimum length
cables and make certain that the connections are both physically and electrically sound. With poor
grounding, you may risk damaging your equipment, having problems with TVI/BCI or your transmitted
signal may be distorted.
4.2. Coaxial Cable
The output of the transceiver is to be connected to the input of the amplifier via RG58 or similar
cable. For the connection between the power amplifier and the antenna, RG213 or similar coaxial
cable suited for high power is recommended. All the INPUT and three OUTPUT (ANT1, ANT2, ANT3)
SO-239 sockets with Teflon insulation are used.
Rier view of the amplifier OM2000+
Fuses Mains Plug HF Outputs
Blower Grounding point Control HF Input
4.3. Control Cable
Control cable maintains TX / RX switching of the PA (TX GND). The cable is shielded. On the side of the
power amplifier a CINCH-socket is used. On the side of your transceiver you have to use a socket
suitable for this transceiver. During transmitting the middle pin is connected to the ground. The relays
of the OM2000+ have to be switched earlier than HF is applied (cold switching). Modern transceivers
they have a time delay between PTT switching and power output.
Exhibit 6 Page 11 from 35
CAUTION
If you are using an older transceiver or transmitters without time delay, we recommend to connect
the PA in such a way that the transmit/receive switch (foot switch for example) is connected with
the KEY IN socket of the amplifier. The KEY OUT socket is to be connected with the PTT socket at the
transceiver.
The amplifier is equipped with safety devices, which ensure that the output relay is not switched under
power mistakenly (hot switching).
KEY IN RCA Phono - Input signal PTT switching voltage / current - 5V /2mA)
KEY OUT RCA Phono - Output signal PTT (maximum switching of 30V / 50mA)
4.4. Main Supply
CAUTION
Be sure you got PA with properly terminated line cable, corresponding with your power system’s
outlet. If not, contact your dealer. In such a case you should make the necessary changes using a
licensed electrician.
WARNING!
Be sure that your power system is correctly wired and properly rated! To use adequately sized and
connected grounding system is also very important.
4.5. Cooling
CAUTION
The amplifier must be installed in such a way that free flow of hot air from the tube is allowed. Do
not obstruct air intake and exhaust areas of the PA.
The centrifugal blower provides the necessary cooling of the amplifier, even during long contests. The
blower is activated by switching the PA on and it is turned off when cooling is finished (approx. 1-5 min
after switching off the PA depending on the temperature of the tube). Blower speed (2 steps) is setting
automatically according to the tube temperature.
Detailed view on the tube and blower area.
Antenna switch (above) is installed inside the
metal box.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Exhibit 6 Page 12 from 35
5. OPERATION
WARNING!
Before switching PA on, make sure that amplifier is grounded, antenna or dummy load is connected,
and line cord is putted to the outlet. Be sure you selected AC input by 7.1.
CAUTION
Before switching PA on, check all connections between PA and TCVR.
CAUTION
Do not turn PA on for at least 2 hours after unpacking it and locating in its operating location.
Especially when amplifier is moved from a cold place to a warm one because not visible
condensation may develop, and this could result in damage to the high voltage circuits of the PA.
CAUTION
Never try to change antenna output during a transmission to avoid warranty loss.
NOTE
When you decide to have a short operating break, place the amplifier to the standby mode rather than
switch it off.
5.1. Operation elements
There is couple of operational elements accessible or visible on the front panel.
Exhibit 6 Page 13 from 35
BAND - Band selector switch
TUNE - Anode capacitor for tuning
(higher frequencies to "0"; lower frequencies to „100“).
LOAD - Output capacitor tunes antenna load resistance to the amplifier.
Capacity is low at „100“ and high at "0" on the scale.
WATMETER - Analog double system meter for forward and reflected power measuring
ON / OFF - Long press (abt. 1 sec.) to switch PA ON/OFF
RESET - Short press to reset faults or warnings
0 / I Power ON small 12V APU for logic and protection circuits
You can switch Antenna ports even if PA is switched OFF.
S1 S2 S3 S4
Exhibit 6 Page 14 from 35
ON AIR - Transmitting mode LED
STBY - Standby mode LED
FAULT - Failure LED
ON - PA is „ON“ LED
S1 - OPER / STBY - Press to switch between Standby and Operation mode
ESC - Return to the previous level
S2 - MENU - Enter the Menu
DOWN - Scroll down
S3 - DSP - Change display (DSP1, DSP2, DSP3)
UP - Scroll up
S4 - ANT - Change Antenna output (ANT1, ANT2, ANT3)
ENT - Confirm the selection
More functions of S1-S4 buttons will be described in next parts of this manual.
5.2. Preparation for operation
The first necessary thing after connecting AC to the power amplifier is switching main (green) switch
to „ I “. Welcome message and then starting information appears on the display:
After switching main switch ON welcome
message appears shortly.
Starting message shows which antenna is
connected. To switch PA ON press ON-OFF
button for abt. 1 second.
Warming time takes abt. 210 seconds. It is
possible to enter MENU during this time, but
with limited possibilities (display settings can
be changed, for example).
You can change ANT output, if necessary.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Exhibit 6 Page 15 from 35
If you change DSP during warming time, you lost count down information. Press BACK (S1) to restore
starting message.
When warming time expires, PA switches
itself automatically to the STBY mode.
You have two possibilities now - switch PA to
OPER mode and start operation, OR to go
thru MENU and submenus to set display
parameters, some hardware parameters or to
enter the service menu.
In the STBY mode Antenna output can be changed (ANT1, ANT2, ANT3) by pressing S4.
Display information can be changed, too.
Press S3 to do it.
There are 3 different display settings possible
in the OM2000+. To set display parameters,
go to the next part of this manual for more
details.
5.2.1. Display menu
The OLED display shows couple of parameters or texts. Display has 4 lines. Three of them are editable.
In every line user can select different parameters, using MENU. See next pictures.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Exhibit 6 Page 16 from 35
After pressing MENU (S2) S1–S4 buttons
changed their functions. To edit display
parameters, press DISP button.
Press DIS1 to edit first display.
Now you can define parameters for first three
rows. Start with first line, press 1Row button.
Go UP or DOWN to select desired parameter.
Press ENT to confirm selection.
There are 4 possible settings for the first line (one bar-graph or three pairs of different parameters):
Forward bar-graph
Forward Power _ Reflected Power
Forward Power _ SWR
Plate voltage Up _ Plate current Ip
Second and third line are divided to the left and the right side, editable independently. To each of these
positions one of the 15 different parameters should be set.
If you finish first line settings, press ESC to go
back to the row selection.
To start edit second line, press 2Row button.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Exhibit 6 Page 17 from 35
S2 and S3 now changed their functions.
To edit left side of the second line, press LEFT
button.
Go UP or DOWN to select desired parameter.
Press ENT to confirm selection.
If you finish left side settings, press ESC to go
back to the side selection.
To start edit right side, press RIGHT
button….etc.
Second and third line programmable parameters are:
Forward Power
Reflected Power
Input Power
SWR
TUNE
Temperature
Frequency
Plate voltage – Up
Plate current – Ip
Screen voltage – Us
Screen current – Is
Screen current – graph
Grid voltage – Ug
Grid current Ig
Heating voltage – Uf
5.2.2. Settings menu
Settings menu offers EBS settings, factory default parameters restoring and display contrast settings
(software version 6.1. or higher).
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Exhibit 6 Page 18 from 35
Electronic Bias Settings (EBS) is one of significant feature of the power amplifier. It allows to set low
plate current after pressing the PTT regardless of whether you have CW or SSB mode, until RF signal
is no present at the input. At the moment when RF signal comes to the input of PA, bias will
automatically change to its working value.
EBS level means level of the Input power, where EBS starts working. Default EBS value is 0.2 W. We
recommend using EBS ON. Significant accompaniment of used EBS is temperature reducing.
To enter Settings menu, go to MENU first,
then press SET button.
Use UP or DOWN button to select EBS
ON/OFF. Press ENT to enter EBS status
settings.
Press ON or OFF to set status of EBS. Press
ENT to confirm selection.
Press ESC to go one level back.
Use UP or DOWN button to select EBS level
parameter. Press ENT to enter EBS level
settings.
Use UP or DOWN button to set EBS level
value. Press ENT to confirm EBS level value.
Press ESC to go one level back.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Exhibit 6 Page 19 from 35
If you wish to restore factory default
parameters, use UP or DOWN button to
select Restore default parameters. Then
press ENT.
Press YES for 1 second to confirm restoring.
Use UP or DOWN button to select LCD
contrast. Press ENT.
Use UP or DOWN button to set contrast value.
Press ENT to confirm settings.
5.2.3. Service menu
In the Service menu it is possible to verify software version. This menu allows user to check total
operating hours and listing in the memory, where reported faults and warning messages are stored.
You can display particularly warning messages and particularly error messages. See chapter 6 for more
information regarding to warnings and faults occurrence. There you can find a coding table together
with a limited values for the safety circuits activation also.
In the Service menu a value of EBS1 and EBS2 can be automatically adjusted. This is used for example
when it is necessary to make adjustment after replacing the tube. Automatic control of EBS, however,
can be done at any time. EBS1 default value is 20mA of Ip, EBS2 default value is 250mA of Ip.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Exhibit 6 Page 20 from 35
Use Service menu after replacing the tube.
This is step No. 1.
To enter Service menu, go to the MENU first,
then press SERV button.
Use UP or DOWN button to check software
version.
Use UP or DOWN button to select Time ON
parameter. Press ENT to see total operating
hours of the PA.
Press ESC to go back to the Service menu.
Use UP or DOWN button to select Faults.
Press ENT to see fault numbers or letters (see
the table in chapter 6).
Press ESC to go back to the Service menu.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Exhibit 6 Page 21 from 35
Use UP or DOWN button to select Warnings.
Press ENT to see warning numbers or letters
(see the table in chapter 6).
Press ESC to go back to the Service menu.
Use this procedure after replacing the tube.
This is step No. 2.
Scroll UP or DOWN to select EBS1 settings.
Press ENT to start automatic adjustment of
EBS1 (20 mA).
Automatically increasing of the grid voltage
(decrease of the negative value) causes a
gradual increase in the plate current. In the
moment, when Ip reaches 20mA, adjustment
stops. Press ESC after stopping.
Use this procedure after replacing the tube.
This is step No. 3.
Scroll UP or DOWN to select EBS2 settings.
Press ENT to start automatic adjustment of
EBS2 (250 mA).
Automatically increasing of the grid voltage
(decrease of the negative value) causes a
gradual increase in the plate current. In the
moment, when Ip reaches 250mA, adjustment
stops. Press ESC after stopping.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Exhibit 6 Page 22 from 35
Use UP or DOWN to select Calibration Ip & Is.
Press ENT to do it.
Ip and Is calibration runs in the background.
Result only is visible on the display.
Press ESC to go one level back.
5.3. Operation mode
CAUTION
In STBY the amplifier is in bypass-mode and your transceiver is directly connected to the
antenna. Maximum allowed power in bypass mode is 100 Watts! Passing RF power is
measured with analog wattmeter only. It is not displayed if PA is either in standby mode
or turned OFF.
Press OPER to activate operation mode.
STBY LED switched OFF.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Exhibit 6 Page 23 from 35
Changing of DSP allows user to watch couple
of basic parameters of the PA in operation
mode without input RF signal. Notice: These
are three default display settings (software
version 6.1.)
Check all connections again. Set BAND selector, TUNE and LOAD capacitors according to
TCVR parameters and delivered tuning table (see next part for more details). Apply low input
power and press PTT. Check Analog wattmeter first. Try to tune PA for maximum output
power and minimum SWR.
Using foot switch in „KEY IN” we
activated transmitting mode of the PA
first.
“ON AIR” LED is ON.
EBS is active (Ip = 20mA)
In the transmitting mode all 4 buttons
(S1, S2, S3, and S4) are blocked!
An example of standard tuning procedure
using Analog wattmeter.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Exhibit 6 Page 24 from 35
5.4. Tuning of the Power Amplifier
The OM2000+ power amplifier is operated in class AB. Thus it’s possible to obtain a maximum output
power at excellent linearity. For this purpose the amplifier has to be tuned carefully.
CAUTION
The operation of a mistuned PA will cause malfunctions, the increase of grid current and problems
with TVI/BCI.
CAUTION
If the input power is higher than 10W and the power amplifier is NOT correctly tuned, the safety
devices will switch it to STBY. After switching the amplifier to STBY, you need to switch it back to
the OPER mode by pressing RESET button shortly.
A tuning table is delivered with the power amplifier. For coarse tuning select a band with BAND switch
and choose the setting of “TUNE” and “LOAD” capacitors according to the table.
Band (MHz)
Tune
Load
Input PWR (W)
Output PWR (W)
1.845
70
45
75
1500
3.630
69
51
72
1500
7.050
50
90
71
1500
10.125
72
28
72
1500
14.175
69
40
70
1500
18.150
81
48
69
1500
21.230
47
67
65
1500
24.940
61
64
59
1500
28.450
33
76
52
1500
50.200
22
90
64
1500
NOTE
Delivered tuning table was made for 50 Ohm loading of PA (dummy load). Each amplifier should have
different values depending on used frequency and used type of antenna. Make your own table valid
for your real conditions.
There are two ways how to do fine tuning. The first method uses a gradual increase in the input power
when tuning the PA (as most operators accustomed). In every case we recommend adjust the display
for both of methods so it shows two parameters important for fine tuning - TUNE and Is graph (> l <).
Exhibit 6 Page 25 from 35
Press OPER to enter operation mode. Apply low input power and press PTT. Be sure you selected right
BAND, TUNE and LOAD knob positions. If you made some mistake, fault message appears:
Safety circuit stopped transmitting, fault LED
is ON (Fault code 4 is saving to the memory).
Release PTT, set proper positions of BAND,
TUNE and LOAD according to the table and
press PTT again.
Another mistake can occur, if you have antenna connected to the wrong output. In such a case „SWR
is too high“ error message appears. Change antenna output using S4 button.
This is not an optimal result, TUNE indicator
must go between both arrows. Use TUNE
knob to get maximum output power and
LOAD knob to get indicator between
arrows.
Another example of not optimal result, TUNE
indicator must go between both arrows. Use
TUNE knob to get maximum output power
and LOAD knob to get indicator between
arrows (in arrows direction).
This is a good result of tuning.
Now increase input power slowly and watch
the display.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Exhibit 6 Page 26 from 35
Two of important information is visible –
screen current increased, but still is within
the allowed limits. Turn LOAD knob slightly
in arrows direction to get TUNE indicator
between arrows.
Display indicates correct tuning of the Power
amplifier.
Remember
Always use TUNE knob to get maximum output power. Use LOAD knob to get TUNE indicator on the
display to the middle position between both arrows. Simultaneously check if Is graph indicator stays
within the boundaries. Repeat both steps more times.
Proper operation mode of FU-728F requires the plate voltage to be close to 3 kV. If anode voltage
without RF power is much lower, watch the heating voltage, too. Normally, heating voltage must be in
boundaries from 8.5 to 9 V without RF signal (DSP3). Heating voltage level is a reliable indicator of
correct AC selector adjustment. If you see heating voltage lower than 8.5V without RF signal, change
primary AC voltage selector one step down (if possible). Conversely, if the voltage is higher than 9V,
try to move AC selector one step up (for example from 220 to 230 VAC). Check heating voltage under
full load (full output power), also. If the heating voltage without RF signal is OK but under full load
drops more than 1.5 V, this relates to the „soft“ AC network and is solvable only by „changing“ the AC
network...
Without RF power the plate voltage is OK.
Without RF power the plate voltage is 2.85 kV.
Check the heating voltage, too. If it is below
8.5 V, this indicates the need to change AC
selector position one step down (for example
from 230 to 220 VAC).
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Exhibit 6 Page 27 from 35
To start the second method of fine tuning, press S2 (TUNE) button in OPER mode.
PA is in the operation mode. After TUNE
button (S2) was pressed, it changes its
function. Now STOP is blinking.
Do not press STOP button yet!
Apply input power according tune table (or lower) for selected band and press PTT. Use TUNE knob to
get maximum output power. Use LOAD knob to get Is graph indicator within the boundaries.
Display shows properly tuned PA.
TUNE indicator is in the middle, Screen
current is higher, but still inside the limits.
After proper fine tuning release PTT and press STOP button. PA is now prepared for operation.
View on the properly tuned PA. Analog
wattmeter shows forwarded and reflected
power.
After this procedure the amplifier is tuned correctly and ready to give 1500 W output power in all
operation modes. At optimal tuning and full output power a positive max. 50mA current goes through
the second grid.
CAUTION
If the amplifier demonstrate any malfunctions during tuning or it does not behave in accordance
witch the description, interrupt the tuning procedure immediately and check the amplifier! Be sure
not to do any mistakes in choosing bands or TUNE/LOAD values! Be sure that VSWR is not higher
than 2:1 and input power is LOW!
After excluding possible human mistakes you will be able to work for long time with this amplifier!
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Exhibit 6 Page 28 from 35
6. MAINTENANCE
6.1. Indication of Fault Conditions
If a fault condition appears during the operation of the amplifier, the safety circuits of OM2000+ will
react. There are several warning or fault messages possible to appear on the display, when some of
the protection will be activated. The OM2000+ power amplifier can report one of the following
messages:
1 - Power Out is too high
2 - Refl. power too high
3 - Power In is too high
4 - Low output power (tune)
5 - Plate current too high
6 - Grid current is high
7 - Screen current error
8 - N/A
9 - Heating voltage error
A - HARD FAULT
B - Plate voltage error
C - Grid voltage is low
D - Screen voltage error
E - SWR is too high
F - Amplifier is too hot
NOTE
Most of safety circuits are preset for two levels of exceedances. First level is a warning level. In such a
case a warning message appears on the display, fault LED will flash, but power amplifier will stay in
normal operation. See the table below for warning and fault conditions.
NOTE
When a fault condition appears during the tuning or operation of the amplifier, the safety circuits will
block transmitting and FAULT LED starts blinking. The amplifier stays in OPER mode. After approx. 1
sec the control circuits will automatically switch the amplifier back to the transmitting mode. If
problem persists, safety circuit will react again.
CAUTION
If the fault will repeat 3 times during 10 seconds, the safety circuits will turn the amplifier to STBY
mode. FAULT LED stays ON. To cancel fault status, press RESET shortly. Power amplifier will stay in
STBY mode.
All the warning and fault messages are stored in the memory. You can display particularly warning
messages and particularly error messages. See the Service menu in the 5.2.3., how to select service
display. All of messages are stored and displayed as a numbers or letters as indicated in this chapter (1
- 9; A - F). They are stored one by one to the memory. You can see them on the display in three lines,
on every second display position (maximum 10 per row, maximum 30 messages for warnings and 30
messages for errors). If memory is full, every new message will delete oldest one and move rest of
Exhibit 6 Page 29 from 35
them one position back. It means that every time last 30 messages are visible on the display. Next table
shows limited values for the safety circuits activation.
Fault code
Parameter
Warning level
Fault level
1
Power Output is too high
2200W
1700W (50MHz)
2300W
1800 (50MHz)
2
Reflected power is too high
250W
300W
3
Power Input is too high
80W
100W
4
Low output power (tune)
> 3dB below*
5
Plate current is too high
1.8A
2.0A
6
Grid current is too high
10mA
20mA
7
Screen current is too high
50mA
60mA
8
N/A
N/A
9
Heating voltage error
+/- 2V ***
+/- 2.5V
A
HARD FAULT (from 3.1 version)
Plate current >2.5A
****
B
Plate voltage error
Min. 1800V
Max. 3400V
Min. 1500V
Max. 3500V
C
Grid voltage is low
-40V
-30V
D
Screen voltage error
Min. 250V
Max. 400V
Min. 220V
Max. 420V
E
SWR is too high
3:1
F
Amplifier is too hot
80 deg. C *****
90 deg. C *****
1. * This fault indicates mistuning of the PA. It works for Input power higher than 10W. If output
power decreases more than 3dB below value corresponding with the applied Input power,
fault message „Low output power“ appears. You have to tune the PA correctly.
2. *** When the heating voltage exceeds boundaries 9V +/- 2V, warning message „Heating
voltage error“ appears. Check proper position of AC selector (page 25). Heating voltage
without RF signal should be between 8.5 and 9V.
3. **** „HARD FAULT” appears if the plate current exceeds 2.5 A. In such a situation hardware
will immediately disconnect high voltage from the plate. Fault is signed with the letter „A“ in
the memory. If error occurs frequently, consult this situation with the manufacturer, please.
4. ***** If temperature sensor inside the PA detects of 80 deg. Celsius, warning message
„Amplifier is too hot“ appears on the display. At 90 degrees protection circuit will
automatically block transmitting (fault condition). You have to decrease the power or wait
couple of minutes to be ready transmitting again. Fault is signed with the letter „F“ in the
memory.
Exhibit 6 Page 30 from 35
An example shows situation when Input
power is too high. By pressing PTT safety
circuit will react quickly, error message
appears and FAULT LED starts blinking. In
this case screen current exceeds limited
value (60mA).
After abt. 1 sec. PA returns to TX mode.
Reduce Input power to avoid fault repeating.
This is the situation, when problem with high
Input power persists. Safety circuits reacted
3 times, and then switched PA to STBY mode.
Permanent fault appears.
To return PA to the normal operation,
decrease Input power first, then reset fault
status and go back to the OPER mode.
If resistor R1 or fuse F3 is damaged, safety
circuit stops starting of the PA and fault
message appears on the display. It is
necessary to replace the damaged
component.
Fuse F3
Resistor R1
If there is a fault condition, always try to remove the cause first. If it is not a hardware failure, it usually
succeeds. For example high VSWR, high Input power, mistune of PA, high temperature, etc.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Exhibit 6 Page 31 from 35
In the case of some hardware failure or if your power amplifier is not working properly, please contact
the manufacturer or your dealer.
WARNING!
Never try to change or move any part inside the amplifier except of tube or fuses. Substitution of
parts may void intrinsic safety!
Manufacturer’s contacts: OM POWER, s.r.o.
930 30 Báč 126
SLOVAKIA
Email: om-power@om-power.com
6.2. Fuse Replacement
The user is allowed to change mains fuses (6.3 x 32mm), accessible from the rear panel, only. In the
case of fuse (fuses) interruption inside the power amplifier, exchange can be carried out only by
professionally qualified person! Internal fuses are located mainly on the SWITCH-on board (next to
the HV transformer).
One special fuse is used in the model
OM2000+. In the case of an accidental
discharges in the tube this fuse saves HV
supply circuits.
Fuse
6.3. Tube Replacement
In the case of vacuum tube damaging, contact the manufacturer or your dealer for ordering new one.
You will get instructuions how to change it. Exchange can be carried out only by professionally
qualified person! After tube replacing automatic BIAS adjustment must be done. Read Service menu
(5.2.3.) and pictures on page No. 20 for more details.
6.4. Cleaning
To prevent damage to amplifier surface and plastic components do not use aggressive chemicals for
cleaning. Do not open the amplifier for cleaning. Outer surface may be safely accomplished by using
piece of soft cotton cloth moistured with clean water or window cleaner.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Exhibit 6 Page 32 from 35
7. APPENDIX
7.1. Primary AC voltage selection
Primary section of the HV transformer is switchable for three values of AC voltage (220, 230, 240V).
Factory settings is 230VAC. Before first starting of the PA we recommend to check the correct value
according to the AC voltage in your network. Change the settings, if necessary.
Side view on the opened OM2000+
HV Transformer AC Selector
Exhibit 6 Page 33 from 35
Remove the upper lid first. On the right side of the PA, next to the HV transformer there are two
PCBs mounted. On the left upper side of the front (Switch-ON) board connector J6 is located.
Use flat screwdriver or finger and press
carefully the white stick to release contact
and move upper end of the white jumper to
the proper position, if necessary.
Jumper must be connected between bottom
contact and one of remaining contacts. AC
voltage is marked next to every contact.
NOTE
AC selector range can be changed in the production according to the specific conditions in individual
countries.
7.2. Removing the HV Transformer
For simpler and easier transport of the PA, HV transformer can be removed and taken separately. This
distributes the weight of the PA (24 kg) about half and half. Follow next steps to do it.
1. Remove upper lid from the PA.
2. Turn the PA on the left side (transformer is up).
3. Disconnect 3 connectors from the front board and 1 connector from the rear board.
4. Release 4 screws from the bottom side of the PA. Use Philips screwdriver P2. During the release
of the last 2 screws hold the transformer by hand. Do not worry about its weight, it will move
down just 1 cm and remains on the central rung of the PA.
5. Use both hands to take transformer away from the chassis.
Watch the released terminals, when moving
the transformer!
Do not damage transformer insulation during
removing and transportation.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Exhibit 6 Page 34 from 35
Weight of the PA was distributed (transformer
has 12 kg, rest of the PA has cca 12 kg, too).
When refitting the transformer, watch to the correct location of individual sections and wires.
NOTE
Manufacturer reserves the right to make future changes in the way of connecting the transformer to the
board. Allways mark the position of the terminals before disconnecting the transformer.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.
Exhibit 6 Page 35 from 35
7.3. Block Diagram of OM2000+ Power Amplifier
J4
J12
J3
Ext. blower
J10
!
J8 K1
K6
CONTROL BOARD
DISPLAY
ANT SWITCH
K2 K1
K1
J3
A3
A2
A1
K3
K7
K2K1
K11
K4
K8
J3J2
J1
K3
J1 J11 K1
K2
J15 J14
J8
J9
J7
J2
J13
AC IN
J4
24V
Rev.: 10.2.2014
K2 K1
Cover SW
OM 2000+ block diagram
L8L7
SW 1cSW 1bSW 1a
FU728f
Rele GS
KEY IN
KEY OUT
TR 1
Blower
ON
SW ON BOARD HV SUPPLY
METER BOARD
OUTPUT
AC
INPUT
PWR METER
SCREEN BOARD
INPUT BOARD
1
R1
2
1
47
C2
2
1
1
L10
2
1
L6
2
T 16A
21
1
1
F 4A
F3
2
1
1
2
T 16A
21
2
1
3
2
1
K1
21
1
4
53
1
2
1
L4
2
212121
2
1
2
1
2
1
2
1
2
1
2
1
2
1
21
21
21
21
1
2
1
2
21
1 2
1
21