MANUAL P/N 900000035 REV C
12
5 Maintenance
and
Troubleshooting
There is no preventive maintenance required for the FDU-240.
SYMPTOM
POTENTIAL CAUSE
CORRECTIVE ACTION
No signal
outputs
1. There is no input
reference.
2. The Reference Select
switch is selecting
Reference B when an
internal OCXO is used.
3. There is a failed internal
source.
1. Connect the reference
input.
2. Select an internal source.
3. Return to factory for repair.
Fault light
illuminated
1. There is an internal
OCXO failure.
2. There is a failed output
driver.
3. There is an excessive
load on one or more
outputs.
4. The output level is
adjusted too low.
1. Return to factory for repair.
2. Return to factory for repair.
3. Disconnect the output
loads one by one until the
overloaded output is
isolated. Outputs should
not have a load < 50 ohm.
4. Isolate the low output level
and adjust for a level that
is > 10 dBm.
