Keysight E8257D/67D - Self-Tests 7 Xx: A45 Frac-N Self-Test Errors (Option UNY)

E8257D/67D, E8663D PSG Signal Generators Service Guide
Troubleshooting
Troubleshooting Assembly–Level Problems
1-41
3. If all of the signals at J1 are good, turn the signal generator off and reinstall the A6 Frac–N.
4. Check J4 at the A8 Output (shown on page 1- 58):
a. Power the signal generator on and remove the A8 Output.
b. Use an extender cable to connect a spectrum analyzer to J4.
c. Tune the spectrum analyzer to the first frequency in column one of Table 1- 15, and check for approximately
+10 dBm.
• If an RF signal is present on J4, replace the A8 Output.
• If an RF signal is not present on J4, replace the A6 Frac–N.
705 F/2 Test
1. Using an oscilloscope, check the 10 MHz Synthesis line on P33–15. The signal period should be 100 ns with an
amplitude of approximately 3V
pp
.
• If the signal is good, replace the A6 Frac–N.
2. If the signal is bad, turn the signal generator power off, remove the A6 Frac–N, and measure P33–15 again.
• If the signal is good, replace the A6 Frac–N.
3. If the signal is still bad, measure P41–5 on the A7 Reference.
• If the signal is good at P41–5, replace the A31 Motherboard.
• If the signal is bad at P41–5, replace the A7 Reference.
706 FM Path Test
1. Using an oscilloscope, check P31–22 (FM_On_H):
a. Loop self–test 706
b. Check for a TTL transition from 0 Vdc to +5 Vdc.
• If the signal is not present, refer to A5 Sampler troubleshooting.
2. If the signal is present, check P31–11 (FM):
a. Loop self–test 706.
b. Check for a 0 to 3.3 Vdc transition.
• If the signals is present, replace the A6 Frac–N.
• If the signal is not present, refer to A11 Pulse/Analog Modulation Generator troubleshooting.
707 Sweep Phase Detector Test
1. Replace the A6 Frac–N.
Self–Tests 7xx: A45 Frac–N Self–Test Errors (option UNY)
720 Ref Voltage Test
• Replace the A45.
721 1 GHz Input Test
Disconnect the cable W155 from the Frac- N A45J4 and connect to a signal analyzer. Check for 1 GHz and its power,
aproximately 0 dBm.
• If the signal is present, replace A45.
• If the signal is not present, replace W155 or A46.
722 Open Loop VCO Test
• Replace the A45.