OM POWER OM4001A User manual

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MADE IN SLOVAKIA
WWW.OM-POWER.COM
OM Power, s.r.o. 93030 Báč126,
SLOVAKI A
Co n t a ct : + 4 2 1 905 321 410
e-mail : [e-mail]
e-mail : om-power@om-
power.com
OM4001A
SHORTWAVE
POWER AMPLIFIER

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TABLE OF CONTENTS
1. GENERAL INFORMATION .................................................................... 4
1.1. Introduction ………………………………………………………. 4
1.2. Specification ………………………………………………………. 4
1.2.1. Parameters ………………………………………………. 4
1.2.2. Protection Circuits ………………………………………………. 5
1.2.3. Features ………………………………………………………. 5
1.2.4. The Advantages of OM4001A …………………………………… 5
2. SAFETY INSTRUCTIONS ………………………………………………. 6
3. GENERAL DESCRIPTION ………………………………………………. 7
3.1. HF Compartment …………………………………………………………. 7
3.2. Power Supply …………………………………………………………. 9
3.3. Safety Devices …………………………………………………………. 9
4. INSTALLATION ………………………………………………………. 9
4.1. Grounding ……………….………………………………. 10
4.2. Coaxial Cable ………………………………………………. 10
4.3. Control Cable ………………………………………………. 11
4.4. Cooling ………………………………………………. 11
5. OPERATION ………………………………………………………. 12
5.1. OM4001A Front Panel ……………………………………………. 12
5.2. OM4001A Control ………………………………………………… 13
5.3. Preparing for operation ………………………………………… 20
5.4. Operation mode ……………………………………………………. 26
6. MAINTENANCE ……………………………………………. 30
6.1. Indication of Fault Conditions ………………………………… 30
6.2. Fuse Replacement ……………………………………………. 31
6.3. Tube Replacement ……………………………………………. 32
6.4. Cleaning ………………………………………………. 32

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7. APPENDIX ………………………………………………………. 32
7.1. Primary AC selection ……………………………………………. 32
7.2. Controlling OM4001A with FLEX Radio Series 6xxx ……………. 34
7.3. OM4001A Remote Control ………………………………..………. 36
7.4. Remote Control using own public IP Address ............................. 40
7.4.1. Changing OM4001A+ connection settings ................................. 40
7.4.2. Setting up in the Remote software ............................................... 41
7.4.3. Remote Control without own IP Address, behind a router .......... 42
7.5. OM4001A firmware upgrade …………………………..………… 43
7.6. Icom connection with OM4001A ……………………………….… 47
7.7. Yaesu plus BPF plus ANT Switch connection with OM4001A … 48
7.8. Control panel connectors pin-out …………………………….…… 49
7.9. Block Diagram of the OM4001A Power Amplifier …………..… 53
7.10. Troubleshooting ………………………………………………………. 54

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GENERAL INFORMATION
1.1. Introduction
he OM Power model OM4001A is designed for all short wave amateur bands from 1.8 to
29.7 MHz (including WARC bands) and all modes. It is equipped with a two ceramic
tetrodes FU-728F.
1.2. Specification
1.2.1. Parameters
Frequency Coverage Amateur Bands 1.8 – 29.7 MHz including WARC
Power Output 4000+ W in SSB/CW on HF bands
3000 W in RTTY and DIGI modes
Input Power Usually 40 to 60W for full Output Power
Input Impedance 50 Ohm, VSWR < 1.5 : 1
Power Gain 17 dB
Output Impedance 50 Ohm unbalanced
Maximum Output SWR 3 : 1
SWR protection Automatic switching to STBY, when reflected power
is 350W or higher
Intermodulation distortion -32dB below nominal output
Suppression of harmonics < -50 dBc
Tubes 2 x FU-728F Ceramic tetrode
Cooler Centrifugal blower + Axial blower
Power supply switchable 2 x 220 ,230V, 240 V – 50 Hz one or two
phases
Transformers 2 pcs of toroidal transformer 3kVA
Dimensions 485 x 200 x 455mm (width x height x depth)
Weight 46 kg
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1.2.2. Protection Circuits
There are several protection circuits used in the amplifier. They are activated when one
or more parameters exceed defined values or some unwanted condition occurs.
•VSWR too high
•Anode current too high
•Anode voltage error
•Screen current too high
•Screen voltage error
•Grid current too high
•Grid voltage error
•Heating voltage error
•Mistuning of PA
•Temperature too high
•Soft start for fuse protection
•“switch-on blocking “ at opened amplifier
1.2.3. Features
The manufacturer implemented some of the company’s newest development results with
most wanted operating and safety features into this new model:
•High level of protection
•Memory for faults and warnings, easy maintenance
•Automatic set-up anode current (BIAS) – no need to adjust manually after
changing the tube
•Three programmable working modes of the 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 4000 W Power Amplifier on the market
1.2.4. The Advantages of OM40001A
•Full compatibility with: ICOM, ELECRAFT, KENWOOD, TEN-TEC ORION, YAESU, Icom
transceive protocol using by MicroHAM devices ( CI-V output ), FLEX Radios and
Anan.
•RF sensitive Band and Frequency switching, for use with radios which do not
have CAT. We recommend using CAT and BAND DATA information
due to the much faster band changing whenever possible.
•Automatic switching between bands. Automatic tuning within the band according to segments.
•Automatic switching of Band Pass Filter – BAND DATA output compatible with YAESU radios
(BCD code).
•Automatic switching of Antenna switches. The maximum number of antennas is 10, controlled
by BCD output code.
•Remote control via available PC Application. http://www.om-power.com/download/HF
PA_Manager_

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2. SAFETY INSTRUCTIONS
DANGEROUS HIGH VOLTAGE INSIDE!
The power amplifier is using high voltage up to 3300 V 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 THE FOLLOWING SAFETY RULES!
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!
Never turn the amplifier on without the upper lid in place. DO NOT ATTEMPT TO SHORT
OR BYPASS safety switch under upper lid!
The OM4001A amplifier should not be used in a WET or HUMID environment or be
exposed to RAINFALL!
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!
Before removing the upper lid of the amplifier make sure that power supply has been
disconnected AT LEAST 10 minutes allowing for the electrolytic capacitors to discharge
fully. Disconnect power cord from the outlet!
Any work inside the PA (internal fuses replacement, tube replacement, etc.) should be
carried out only by aprofessionally qualified person!

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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 extended operation the tube ventilation grid can reach high
temperature. Do not touch it!
The amplifier must be properly grounded during operation.
During operation the amplifier must be installed in such a way that the rear side remains
accessible.
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.
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 Compartment
his amplifier is using a par of ceramic tetrode FU-728F in a grounded-cathode circuit
(input into control grids). The OM4001A amplifier achieves excellent linearity by the
voltage stabilization of the control grid bias and the screen voltage. The power input is fed
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.
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The output of the amplifier is a Pi-L circuit. The variable capacitors for TUNE and LOAD are
seperate. 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 OM4001A
Tetrode FU728F Blower Switch-ON Board
Output Pi-L Circuit Tuning Capacitor Front Subpanel Power Supply Board

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3.2. Power Supply
This Power amplifier uses two 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 8 x 420
V (total 3360V) @ 2.5A . 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 separate screen grid supply is regulated and stabilized with MOSFET circuits and delivers
abt. 350V DC at 200mA. Control grid voltage is also stabilized (-120V DC). Change of
stabilized first grid voltage is controlled by the software (EBS for example).
The transformer primary is Tap adjustable for 220 , 230 or 240V AC.
The factory setting is 230 VAC .
If the AC voltage in your network is 220 or 240 Volts, you need to set the correct
transformer tap before first starting the PA. See part 7.1. for more information. Other primary
voltage is possible on request (for example 200V 50/60 Hz for Japan).
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 elements is a
mechanical switch for AC blocking an
opened amplifier.
4. INSTALLATION
Read this chapter carefully prior to starting installation. Before unpacking inspect
shipping carton for any damage. Keep all of packing parts for possible future
shipment. Check unpacked power amplifier. If you find any damage, contact your
dealer immediately to keep full warranty.
Type of supported TCVR and working
frequency are visible on the display.
AUTO LED is ON.

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4.1. Grounding
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, have problems with TVI/BCI or
possible distortion of your transmitted signal.
4.2. Coaxial Cable
The output of the transceiver is to be connected to the input of the amplifier via RG58 or similar
50 Ohm cable. For the connection between the power amplifier and the antenna, RG213 or
similar coaxial cable suited for high power is recommended. SO-239 sockets with Teflon
insulation are used for the HF INPUT and OUTPUT connectors.
Rier view of the amplifier OM4001A
Mains PlugsFuses HF Output
Grounding point Blower Control HF Input

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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 OM4001A have to be switched earlier than HF is applied (cold
switching). Modern transceivers they have a time delay between PTT switching and power
output.
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. If there is
possible to adjust TX delay in your TCVR, set the delay to 15ms, please.
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)
See section 7.9. for Control and ANT/BPF connector PIN-OUT.
Be sure that your power system is correctly wired and properly rated! To use an
adequately sized and connected grounding system is also very important!
4.4. Cooling
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 working mode is programmable (3 modes). See page 20-21 for more details.

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5. OPERATION
Before switching PA on, make sure that amplifier is grounded, antenna or
dummy load is connected, and line cord is plugged into the outlet. Be sure you
have selected the proper AC input TAP (Sect 7.1)
Do not turn PA on for at least 2 hours after unpacking and located in its operating
location. Especially when amplifier is moved from a cold place to a warm one as
condensation may develop. This condition could result in damage to the high
voltage circuits.
We do not recommend changing antennas during a transmission. (Hot switching)
When you decide to have a short operating break, We recommend placing the
amplifier to the standby mode rather than switch it off.
5.1. OM4001A Front Panel
Front panel of the OM4001A is almost empty…Containing only the touch TFT display plus two
control switches.
ON -Main Switch. After turning ON, a small 12V APU for logic, protection circuits and the
display will be activated. High voltage and RF circuits are still OFF.

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OPR/STBY -Short press for switching betwen STBY and OPERATION mode.
ON/OFF -Long press (1 sec.) for switching the PA ON (tube heating first), 2 seconds for
PA OFF. Always use the ON/OFF button as this allows for a predetermined (software
controlled) time to cool down the tube and inside the PA compartment.
5.2. OM4001A control
Turn ON the green Main Power switch and the home screen will lights up. Initial control touch
buttons are visible on the bottom line.
Remember that the home touch screen is active for some information and control settings ,
while the PA is still OFF!
BAND
Touch the left side of BAND button to go down, touch the right site to go up. The band
information is displayed above the button.
ANTENNA
Transmitting antenna choice. Functional ONLY when the antenna switch is programmed and
antennas are defined (see page 17). This antenna feature allows switching between antennas
authorized for the current band. An external antenna switch is controlled by BCD code at the
ANT/BPF output (see Section 7.9).
INFO
Information display shows basic information about the PA: serial number, software version, time
ON, tube serial number and nominal Main voltage.

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The information screen also
provides an overview of the last
20 warnings and faults:
Press FAULTS.
Press EXIT to go back to the home
screen.
Now press SETTINGS. This
display shows various menu
settings for CAT, NO CAT,
ANTENNA, DISPLAY, EBS,
CLEAR user settings for one or all
bands, BLOWER mode and other
INFO.
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.

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Screen shows settings possibilities
for CAT, ANTENNA, DISPLAY,
NETWORK SETTING, EBS,
BLOWER and other INFO.
Scroll to CAT SETTINGS (up or
down) and
press SET.
Scroll to your TCVR family (up or
down)
select appropriate bit rate (left or
right)
then press SET.
Or select NO CAT and press SET.
We recommend using the CAT connection whenever possible because, in such a case, the
OM4001A has permanent information about the transmit frequency and is immediately ready for
transmitting.
With a setting of NO CAT the OM4001A detects transmit frequency from the input signal. With
the input signal frequency changing the PA automatically reacts and tunes itself to optimal
output parameters.. If NO CAT is used, we recommend using BAND DATA (BCD) information
for much faster band changing.
If you choose YAESU or ICOM
NEW, after SET pressing you will
go to deeper level which allows
you to select specific type of
TCVR.ee the following picture for
ICOM NEW selection, for example.
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.

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You selected IC7800 addr.6AH
and 19200 Bd. Press SET to write
to the memory, then press EXIT to
go back to the SETTINGS
possibilities.
“SET OTHER ADDRESS” means
that you must add here a new type
of ICOM TCVR which is not
defined in the table (its address
plus bitrate in Bd) to allow
communications with it.
Press ANTENNA SETTINGS. First
select ANTENNA SWITCH (No
switch, Standard). Use left or right
arrows. If you select some switch,
10 ports for different antennas
displays. Generally all of antennas
are allowed in every band (green
squares). To disable some square
select port (up/down), touch SET
for antenna name and then select
band (left/right). Press SET.
Four types of antennas for four
different bands were disabled.
Black square means disabled
combination.
Press EXIT to go back to
SETTINGS menu
BCD code (4 bits) is used for automatic antenna and BPF switching (see Antenna/BPF
connector on the Control panel (rear side of the PA). See section 7.9 for Control and
ANT/BPF connectors pin-out.
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.

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Next SETTINGS position is for
display parameters. First choose the
background color. Scroll on it and
choose the color (left/right).
Press SAVE twice, then scroll to
OWN CALL.
Press SET for your callsign edit. The
keyboard displays.
Type your callsign and press ENT.
Use next lines and set brightness and
sound volume (use up/down and
left/right). Confirm with SAVE.
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.

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Press NETWORK SETTING and
then press ENTER.
Here the user has the option to set
IP Address, Network mask,
Default gateway, Port number.
User can enable or disable IP
parameter setting via LAN
connection.
Next lines are for EBS (Electronic
Bias Setting) ON/OFF and for
EBS level selection.
We recommend EBS ON. See
next comment for more details.
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.

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Electronic Bias Settings (EBS) is a significant feature of this power amplifier. It automatically
allows lower plate current after pressing the PTT, regardless of whether operating CW or SSB
mode, when no RF signal is present at the input. At the moment an RF signal is applied, the
bias will automatically change to its working value.
EBS level means level of the Input power where EBS starts working. Default EBS value is 0.1
W. We recommend turning EBS ON. A significant feature of using EBS is PA operating
temperature reduction.
NOTE: If you are not using compression in your TCVR,or you are not speaking loud enough,
some syllables can be cut off. In such a case you should turn OFF the EBS.
The next two settings allow
deletion of the manual user
settings of the amplifier tunings
for a single band or for all
bands.
Settings in all segments will
return to the factory default
values (for 50 Ohms).
In the next line you can define
working mode of the blower. In
the first mode speed depends
on the PA temperature (TEMP),
In PTT mode the speed
increases to maximum, and the
ALLWAYS mode means
maximum speed all the time
during PA operation
(recommended for DIGI
modes).
Press SAVE to write the mode to the memory.
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.

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The INFO settings allows
viewing all of the previous PA
INFORMATION screen plus the
addition of one more touch key
to enter the UPGRADE mode.
UPGRADE touch button
should ONLY be used if the
EEPROM or firmware files (or
both) will be upgraded. In such
a case ask the dealer or
manufacturer for the exact
procedure.
5.3. Preparing for operation
In STBY the amplifier is in bypass-mode and your transceiver is directly
connected to the antenna. Maximum allowed power in bypass mode is 200 Watts!
The bypass RF power is displayed if PA is in standby mode.
To turn PA ON press ON/OFF button on the front panel (black one) and hold it abt. 1 second.
PA will start tube heating. It will take 180 seconds. Turning PA ON is possible ONLY from the
home screen! If you have other display active, press EXIT more times to go back to the home
screen. (These same functions are also available on the OM Power Remote Control PC
Application)
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.