Rohde & Schwarz 1164.4391.03, Service Manual

Page: 186 / 254

Troubleshooting R&S FSP
1164.4556.82 3.82 E-1
Operating Voltages
When an operating voltage fails, the selftest is aborted to avoid subsequent error.
The test is not aborted under service level 1. All subsequent errors are then listed in the result record.
Errors which occurred independent of the voltage failure can then be detected, still.
The error message indicates the error source (power supply, IF filter, detector board) and the voltage
which failed.
Normal action Error and error cause
Power Supply
The voltages of the power supply and the –6 V
regulator (dc-dc converter from –12 V to –6 V on
the motherboard) are measured at the board
connector by means of the selftest A/D-converter
on the detector board.
Channel Nominal voltage
1 +6 V
2 +8 V
3 +12 V
4 -12 V
5 +28 V
7 -6 V
FATAL ERROR!
Power supply: DC FAIL +6 V.
Selftest aborted.
If error messages occur, the voltages on the
motherboard should be checked. The
tolerances given in the column "Tolerance
range power supply / voltage regulator" apply
in this case. If the voltages adhere to the
tolerance limits, the error must be located in
the selftest:
Replace the detector board.
Regulated Voltages on the Boards
Detector Board
Channel Nominal voltage
6 -5 V
FATAL ERROR!
Detector: DC FAIL -5V.
Selftest aborted.
If the preceding tests passed, the detector
board has to be replaced.