E8257D/67D, E8663D PSG Signal Generators Service Guide 79
Troubleshooting
Troubleshooting Assembly–Level Problems
2. Tune the source across the lowband frequencies (250 kHz to 3.2 GHz) and
record the lowest power level.
3. Disconnect the cable coming from the A29 20 GHz Doubler, and connect
the spectrum analyzer to this cable.
4. Tune the source across the A29 20 GHz Doubler band of frequencies
(3.2 GHz to 20 GHz) and record the lowest power level.
5. Determine the expected levels using the tools described in
“Troubleshooting RF Power Levels” on page 122, and compare them to the
measured levels.
— If the power level in both paths is good, replace the A30 Modulation
Filter.
— If the power level in either path is bad, troubleshoot that path.
— If the power level in both paths is bad, check the signal levels out of
the A28 YIG Oscillator.
1202 A29 20 GHz Doubler
1. Disconnect the cable between the A28 YIG Oscillator and the A29 20 GHz
Doubler, and connect a spectrum analyzer to the cable.
2. Tune the source frequency across the A28 YIG Oscillator range (3.2 GHz to
10 GHz) noting the lowest power level.
3. Determine the expected levels using the tools described in
“Troubleshooting RF Power Levels” on page 122, and compare them to the
measured levels.
— If the power level is good, replace the A29 20 GHz Doubler.
— If the power level is bad, replace the A28 YIG Oscillator.
1203 40 GHz Doubler (Option 540)
1. Disconnect the 0 to 20 GHz cable between the A30 Modulation Filter and
the A27 40 GHz Doubler, and connect a spectrum analyzer to the cable.
2. Tune the source from 250 kHz to 20 GHz, and record the lowest power
level.
3. Disconnect the 10 to 20 GHz cable that comes from the A30 Modulation
Filter, and connect the spectrum analyzer to this cable.
4. Tune the source from 20 GHz to 40 GHz, recording the lowest power level.
5. Determine the expected levels using the tools described in
“Troubleshooting RF Power Levels” on page 122, and compare them to the
measured levels.
— If both power levels are good, replace the A27 40 GHz Doubler.
— If either power level is bad, troubleshoot the path.
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