E8257D/67D, E8663D PSG Signal Generators Service Guide
Troubleshooting
Troubleshooting Unlocks
1-65
512 A7 Reference Unlock
The instrument’s reference is unlocked. Use the following list to troubleshoot the problem.
NOTE The error message remains until it is cleared. Ensure that you clear the error message prior to each check to
properly determine whether the error still persists.
• If an external reference is connected:
1. Measure the external reference signal frequency.
2. Measure the external reference signal power level.
3. Compare the results from Step 1 and Step 2 against the specifications found in the E82x7D PSG data sheet.
4. Check the connection to the PSG along with the connectors.
5. Connect a different external reference source.
6. If the error persists, replace the A7 reference board:
• If the error occurs when you initially connect or disconnect the external reference:
1. Clear the error queue: press
Utility > Error Info > Clear Error Queue(s).
2. With no changes to the external reference connection, check to ensure that the error does not reappear.
3. If the error reappears, replace the A7 reference board.
• If none of the above apply, replace the A7 reference board.
513 1 GHz Out of Lock
A 513 1 GHz Out of Lock message indicates a failure on the A7 Reference.
• Replace the A7 Reference.
514 Reference Oven Cold
The Reference Oven Cold Error message indicated the reference has not been connected to electrical power for 30
minutes. This message appears when the signal generator is unplugged or the reference assembly is removed. The
message is controlled by a timer and should turn off after 30 minutes. This is not a failure unless the message does
not go off after 30 minutes. If it continues to be displayed after 30 minutes, replace the A7 Reference.
515 10 MHz Signal Bad
A 515 10 MHz Signal Bad message indicates a problem on the A7 Reference.
A7 Reference (Standard)
• Replace the A7 Reference.
A7 Reference (Option UNR/UNX)
1. Check the 10 MHz signal into the A7 Reference from the 10 MHz standard. The signal should be 10 MHz 1.8 V
pp
into 1 MΩ.
2. If the 10 MHz signal is bad, replace the A32 10 MHz Crystal Oscillator.
3. If the signal is good, replace the A7 Reference.
520 Sampler Unlocked
A 520 Sampler unlock message indicates a failure of the A5 Sampler VCO loop.
1. Run self–test. If self–test fails, troubleshoot the problem reported.
2. Power–up the signal generator. Remove the A5 Sampler. Probe the mmx connection center pin on the right side of
the A31 Motherboard in the A5 Sampler slot. There should be a 1 GHz signal >0 dBm.
3. If the 1 GHz signal is present, replace the A5 Sampler.
4. If the 1 GHz signal is not present, replace the A7 Reference.
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