Keysight Technologies E8257D Service Manual page 72

Troubleshooting
Troubleshooting Assembly–Level Problems
Supply
Vol tage
(Vdc)
+5.2 Digital high
+3.4 Digital Low
900 Power Supply
— Replace the 10 ALC assembly.
901 Detector Test
1. Using a digital voltmeter, check J3 for approximately –0.29 Vdc:
902 Detector Level to ALC Ref
1. Using a digital voltmeter, check J5 for –2.3 Vdc:
2. If the signal is present, check J3 for –0.29 Vdc:
72
Connector Pins
P121–64, 65, 129, 130
P121–60, 61, 62, 63, 125, 126, 127, 128
a. Turn the signal generator's RF power on.
b. Set the frequency to 10 GHz and the RF power level to +20 dBm,
ALC off.
c. Disconnect the cable from J3 of the A10 ALC (W15) and connect the
cable to the voltmeter.
— If the signal is not present, refer to highband RF loop
troubleshooting.
— If the signal is present, replace the A10 ALC.
a. Turn the signal generator's RF power on.
b. Set the frequency to 1 GHz and the RF power level to +20 dBm, ALC
off.
c. Disconnect the cable from J5 of the A10 ALC (W14) and connect the
cable to the voltmeter.
— If the signal is not present, refer to lowband RF loop
troubleshooting.
a. On the signal generator, change the frequency to 10 GHz.
b. Disconnect the cable from J3 of the A10 ALC (W15) and connect the
cable to the voltmeter.
— If the signal is not present, refer to highband RF loop
troubleshooting.
— If the signal is present, replace the A10 ALC.
E8257D/67D, E8663D PSG Signal Generators Service Guide
Minimum Maximum
Value Value
(Vdc) (Vdc)
+5.04 +5.36
+3.29 +3.5
Origin
Main Supply
Main Supply