888-2408-002 6-13
WARNING: Disconnect primary power prior to servicing.
Troubleshooting
6.8 General Troubleshooting Tips
6.8.1 Foldback Conditions
The Master Controller is responsible for transmitter power foldback conditions,
however a foldback condition by itself will not cause a fault to be registered in the
Fault Log. Foldback limits in the transmitter are always set lower than the actual
fault limit. This allows the transmitter to stay on the air at some maximum power
level without shutting off, but since the actual fault level was not reached, no fault
will be logged. If the cause of the foldback goes away the transmitter will return to
full power and no indication of a problem will be evident.
If the front panel FOLDBACK LED is illuminated it is possible to check the
SYSTEM FOLDBACK screen in the Diagnostics Display under [HOME, STATUS
A,B]. This screen shows that there are 3 possible foldback conditions:
• VSWR FOLDBACK YES or NO
• SYSTEM ISO TEMP YES or NO
• IPA FOLDBACK YES or NO
These screens can be extremely helpful in determining where to start looking for the
source of the fault. This screen will only show a YES status if the front panel
FOLDBACK LED is illuminated.
6.8.2 Turning the Transmitter ON with No Power Output
There are times when it is advantageous to be able to turn the transmitter on with the
rf power output at zero watts. This would allow the power to be slowly ramped up
for monitoring of temperatures, currents, voltages and VSWR without over-loading
and tripping the faults circuits. To do this, press the HIGH or LOW ON button and
then quickly press and hold the LOWER button for at least 10 seconds. The
transmitter wil come on but the output power will be at zero.
6.8.3 Asterisk and Pound Signs(*, #)
The asterisk and the pound sign characters are used in some of the metering menus
of the Diagnostics Display. If an asterisk (*) shows up in a metering menu, it means
that there is no data being received for that reading. The pound sign will only be
used in the Vg (Gate Control Voltage for the individual PAs) menus and signifies
that there has been a crossover (this is a condition where one PA Controller crosses
over and mutes the PAs associated with another PA Controller).
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