HP 8647A Operation And Service Manual page 125

613
Description
Cause
What To Do
6 14
Description
Cause
What To Do
615
Description
Cause
What To Do
616
Description
Cause
What to Do
617
Description
Cause
What To Do
Reference o u t - o f - l o c k a t 1GHz
The A4 module indicates that the 1 GHz reference is
Either the A4 module has failed or a bad external
reference is connected.
Replace the A4 module.
out-of-lock.
400 Hzmodulationsourcefailed
The A3 board indicates that the 400 Hz modulation
source is not present.
Either the 200 kHz reference signal from the A4
module has failed, or the A3 has failed.
Check the 200 kHz reference output
of
the A4
module at the input to the A3 board.
1kHzmodulation source f a i l e d
The A3 board indicates that the 1 kHz modulation
source is not present.
Either the 200 kHz reference signal from the A4
modulation source has failed, or the A3 board has
failed. However, if the 400 Hz modulation source has
already been tested, the failure is most likely the A3
board.
Replace the A3 board.
AMmodulationpathfailure
The AM path detector indicates
a
failure at the
output of the A3 board.
Either the signal output has failed, or the detector
has failed.
Replace the A3 board
F M modulation p a t h f a i l u r e
The FM path detector indicates a failure at the output
of the A3 board.
Either the signal output has failed, or the detector
has failed.
Replace the A3 board.
5c-6 Service Error Messages