HP 8647A Operation And Service Manual page 126

618
Description
Cause
What To Do
619
Description
Cause
What To Do
620
Description
Cause
What To Do
625
Description
Cause
What To Do
626
Description
Cause
What To Do
PM modulation path f a i l u r e
The PM 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.
Modulation 20 d B step f a i l u r e
The 20 dB step attenuator has failed.
The A3 board has failed.
Replace the A3 board.
C o m m f a i l u r e
:
A
serial communication failure has occurred with the
indicated assemblies.
Either the A3 controller has failed or the indicated
assembly has failed.
If one assembly has failed, check the indicated
assembly.
If
multiple failures have occurred, check
the controller first. In either case, both the controller
and the assembly should be checked.
ROM checksum f a i l u r e
The A3 controller has detected a mismatch in reading
data from ROM.
Either the controller has failed in reading from ROM,
or the ROM data
has
failed.
Check the hardware connection between the mother
board and the ROM board.
V o l a t i l e RAM read/write f a i l u r e
The controller detected a failure when comparing
data that was written to, and then read from volatile
RAM.
This is a hardware failure between points on the A3
board.
The A3 board failure should be verified and the board
replaced.
Service Error Messages 5c-7