Rohde & Schwarz 1164.4391.03, Service Manual

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Troubleshooting R&S FSP
1164.4556.82 3.70 E-1
Troubleshooting Start-up Problems
•
Error: R&S FSP cannot be switched on.
Action Possible error causes and further steps
Check power-on switch on the rear Power switch OFF: Switch on power supply..
Check yellow LED (Stand-by). LED remains dark:
Measure voltage at X20.D24 (power supply unit)
Rated value: +12 V
±
1V
Voltage o.k.: Keyboard or controller faulty.
No voltage: Remove IF-Filter or OCXO modules.
Measure voltage at X20.D24 (power supply unit):
Rated value: +12 V
±
1V
Correct voltage: Removed module faulty
No voltage:
Power supply faulty or short-
circuit at 12 V standby.
Switch on instrument. Check green LED LED remains dark:
Measure PWR-ON signal on the power supply X20.B1:
< 1V for ON
Voltage > 1 V: Keyboard membrane or controller faulty.
Power supply starts, screen remains dark? Measure voltages on the motherboard, see "Short-
circuit of one or more operating voltages".
•
Error: Short-circuit of one or more operating voltages
Action Possible error causes and further steps
Check on the bottom of the motherboard
which of the voltages is short-circuited:
Computer, hard disk, EEPROMs :
X20.A7 to A10:
rated value: +5 V2
Detector board :
X20.A5 and X20.A6: rated value +3 V3
Analog boards:
X130.A10:
rated value +12 V
X130.A9: rated value +8 V
X130.A8: rated value +6 V
X130.A12: rated value 12 V
No voltage or considerably low voltage:
Remove the respective boards from the instrument one
by one and repeat the measurement.
If the voltage is supplied, then, the error is probably
located on the module removed.
Note: The power supply switches off all voltages after
a short time in case of a short-circuit. Restart
by pressing the Standby/On key.
•
Error: Fan does not work.
Action Possible error causes and further steps
Check voltage at connector:
X35 pins 1+ 3 : rated value 12 V
Voltage o.k.: fan is defective
Voltage too low: fan is blocked or power consumption
too high