Rohde & Schwarz FSP3 Service Manual page 194

Troubleshooting
Normal action
Step Gain (IF Amplifier)
Selftest Detector C (see block diagram)
The 10-dB Step Gain (Step Gain Coarse) and the
0.1 dB Step Gain (Step Gain Fine) are tested. The
input level is attenuated in steps of 10 dB by the
RF attenuator and amplified by means of the Step
Gain by the same amount, simultaneously. The
level detector C checks to ±6 dB (user) or ±4 dB
(service level 1).
1164.4556.82
Error and error cause
FATAL ERROR!
IF Board: Step Gain Fine
Selftest aborted
Test with Step Gain Coarse by-passed (0 dB)
and Step Gain Fine set to 0 dB
If an error occurs, Step Gain Fine does not
work correctly or the signal path is interrupted.
Replace the IF-filter board.
ERROR!
IF Board: Step Gain Coarse
Testing the amplifier stages.
ERROR!
IF Board: Step Gain Fine
Testing the amplifier stages.
ATTENTION: If the RF attenuator test caused
output of an error message, Step Gain
cannot be
message must be ignored
If the RF attenuator test passed without any
error, Step Gain is defective.
Replace the IF-filter board.
However, the selftest can be continued, since
it does not require the IF gain.
3.90
R&S FSP
tested and an error
E-1