Tektronix WFM5250, Service Manual

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Troubleshooting
Table 4: Symptoms and causes (cont.)
Symptom Recommended action
Ground closure input or Alarm output bad Check Reference I/O cable
Replace Reference I/O board
Unknown Problems Use these steps to diagnose an instrument with vague or intermittent symptoms.
1. Check the diagnostic log. This log records a variety of problems and will enable
you to see messages for an error that may not be currently happening
2. Check the power supplies by performing the Diagnostic Monitor Voltage
Checks. A marginal supply can lead to intermittent operation if it is near
the acceptable threshold. This includes the external power source and the
secondary supplies on each board.
3. Perform the incoming inspection tests. This will exercise a majority of the
functions in the unit and includes the Advanced Diagnostics. Some parts of the
test may not be necessary for all problem areas.
WFM5250 Waveform Monitor Service Manual 17