Agilent Technologies 8935 Series, Руководство пользователя

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80 Chapter 3
Troubleshooting
Manual Troubleshooting Procedures (Step 4)
Reference, A2A23, Verification
1. Turn the Test Set off and re-install the Reference assembly.
2. Use screwdrivers to remove the Receiver Synthesizer (A2A22)
assembly.
3. Turn the Test Set on and verify that a 1 MHz signal of
approximately
−
1 dBm is present on pin 3 of J21. This is the
reference signal from the Reference assembly.
4. If the 1 MHz signal is not present, then the Reference assembly is
probably faulty.
It is also possible that an open or shorted trace on the motherboard
assembly exists. Check the motherboard for continuity between J21 pin
3 under the Receiver Synthesizer A2A22 assembly and J18 pin 2 under
the Reference assembly, and verify that the trace is not shorted to
ground.
Receiver Synthesizer, A2A22, Unlocked
If the 1 MHz signal is present on pin 3 of J21, then the Receiver
Synthesizer assembly is faulty.
Signal Generator Synthesizer, A2A25, Unlocked
1. Turn the Test Set off and use screwdrivers to remove the Signal
Generator Synthesizer assembly.
2. If the signal is present, then the Signal Generator Synthesizer
assembly is faulty.
3. Turn the Test Set on and verify that a 1 MHz signal of about
−
20
dBm is present on pin 3 of J12. This is the reference signal from the
Reference (A2A23) assembly.
If the 1 MHz signal is not present, then the Reference (A2A23)
assembly is probably faulty.
It is also possible that an open or shorted trace on the Motherboard
(A2A1) assembly exists. Check the motherboard for continuity between
J12 pin 3 (under the Signal Generator Synthesizer assembly) and J34
pin 1 (under the Reference, A2A23, assembly), and verify that the trace
is not shorted to ground.