Troubleshooting - OM POWER OM2000A+ Manual

7.11 Troubleshooting

The OM2000A+ power amplifier contains several protection circuits, which checked operation. In the case
when some of parameters exceeds normal level, WARNING appears in the LAST EVENS window with
yelllow back colour. If some of parameters exceeds critical level, FAULT is activated and the PA
automatically switch to STBY mode. In the LAST EVENTS window with red back colour fault information
will appear.
All of these events are written to the FAULT and WARNING memories. Last event is visible after LAST
EVENTS button pressing together with information about possible causes.
There are several warning or fault messages possible to appear on the display:
Warning / Fault
Power Out is too high
Refl. power too high
SWR is too high
Power In is too high
Low output power
(tune)
Plate current too high
Grid current is high
Screen current error
Action
Reduce input power
Check your antenna
Reduce output power
Check your antenna
Check antenna switch
Reduce input power
Check amplifier tunning
Tune mistake.
Tune your amplifier
Reduce input power
Check amplifier tunning
Check EBS setting
Reduce input power
Check amplifier tunning
Reduce input power
Check amplifier tunning
Check plate voltage fuse
Description
Output power exceeds maximum level, reduce the input
power.
Reflected power exceeds maximum allowed level. Check if
proper antenna is connected. In the case of higher SWR
reduce the input power and thus the output and reflected
power will be lower.
Antenna SWR is too high (SWR 3 for WARNING and SWR 5
for FAULT). Check if proper antenna is connected. Check
antenna switch configuration, resp. If you want to use
antenna with higher SWR, this protection can be switch off
(page 25). But reflected power will stay checked
(max.350W).
At the PA input is too high input power – decrease it!
If maximum output power is not achievable, check plate
voltage and PA tuning.
The PA has lower gain, may not be properly tuned. Check
plate voltage and Screen current. If they are ok, make
optimal tuning of the PA.
Plate current too high may be for the following reasons:

Too high input power – reduce it

Improper tuning of the PA – bad antenna
impedance matching. Tune the PA properly.

Improper BIAS setting. Check EBS1 and EBS2.
Grid current too high is due to overdriving the PA. Reduce
the input power. If maximum output power is no reachable
due to high plate current, check the PA tuning.
High screen current is usually of the following reasons:

Overdriving the PA – reduce the input power

Improper PA tuning. At maximum output power
the screen current must be inside the range of 0
mA to +30 mA.

Plate voltage is missing. Press PTT without driving
If screen current is higher than +5mA, check plate
fuse (page 32).
60