E8257D/67D, E8663D PSG Signal Generators Service Guide 101
Troubleshooting
Troubleshooting Assembly–Level Problems
2601 Prelevel Loop Test
1. With the signal generator powered on, carefully remove the A8 Output.
2. Set the signal generator to 3 GHz CW.
3. Connect a spectrum analyzer to the A6 Frac–N RF output at J4 of the A8
Output. The signal at J4 should be at 3 GHz and ≥0 dBm.
— If the signal is not present or at the correct level, replace the
Frac–N.
— If the signal is present, replace the A8 Output.
2602 ALC Modulator Test
— Replace the A8 Output.
2603 Pulse Modulator Test
— Replace the A8 Output.
2604 Clamp Detector Test
— Replace the A8 Output.
2605 Bias Switch Test
— Replace the A8 Output.
2606 Switched Filters Test
— Replace the A8 Output.
2607 DAC Functionality Test
— Replace the A8 Output.
2608 Het Band Test
— Replace the A8 Output.
If the A8 Output board has been replaced recently and self test 2201 is
failing, run the ALC Mod Cal adjustment before replacing the A8 Output
board. See Chapter 4, “Post–Repair Procedures.”
Do not re–install the A8 Output with the signal generator powered on. This can
cause serious damage to the signal generator.
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