Troubleshooting - OM POWER OM2000A+ Manual

7.11 Troubleshooting

The OM2000A+ power amplifier contains several protection circuits, which constantly monitor
operation of the Amplifier. When the firmware defined parameters exceed defined operating
levels, a WARNING appears in the LAST EVENTS window of the PA front panel. If some
parameters exceed a defined critical level, a FAULT is activated and the PA will automatically
switch to STBY mode. The LAST EVENTS window will then display the fault information.
All of these events are written to the FAULT and WARNING memories. The Last event is visible
after the LAST EVENTS button is pressed including information about possible causes.
There are several warning or fault messages that may 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 tuning
Tune mistake.
Retune your amplifier
Reduce input power
Check amplifier tuning
Check EBS setting
Reduce input power
Check amplifier tuning
Reduce input power
Check amplifier tuning
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. If you
want to use an antenna with higher SWR, this SWR
protection can be switched off (page 26). But reflected
power will stay checked (max.350W).
PA input is too high – decrease it!
If maximum output power is not achievable, check
plate voltage and PA tuning.
The PA has lower gain and may not be properly tuned.
Check the plate voltage and Screen current. If they are
ok, manually adjust for optimal tuning of the PA. (M-
TUNE)
Plate current too high. Check the following:
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 due to 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 33).
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