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Troubleshooting Procedures
WFM90D and WFM91D Service Manual
6-43
Fault Symptom Table
NOTE. Check the low-voltage power supplies (see Low-Voltage Power Supply on
page 6--42) before proceeding with the following procedure:
1. Disconnect the AC adapter from the instrument.
2. Remove any installed batteries. S ee Batteries on page 6--28.
3. Remove the top cover. See Top Cover on page 6--5.
4. Remove the bottom cover. See Bottom Cover on page 6--31.
CAUTION. To avoid breaking the circuit boards, do not tighten the circuit board
vise too tightly.
5. Secure the instrument circuit boards in the circuit board vise.
6. Connect a 75% color bar test signal to the VIDEO IN connector and connect
the VIDEO OUT connector to the picture monitor.
7. Locate your fault symptom in Table 6--5 and use the indicated flowchart to
isolate the faulty module.
Table 6- 5: Fault symptom table
Symptom Flowchart
No display after pressing the front panel ON button page 6--45
Graticule is good, but the Waveform display is distorted or not visible page 6--46
Graticule is good, but there is no Vector display page 6--47
Graticule is good, but the Audio display is distorted or not visible page 6--49
No display in the Picture display mode page 6--50
Bad graticule and menu, but Picture display mode is good page 6--51
Display all white page 6--52
Waveform display mode sweep not triggered page 6--53
Vector display unlocked page 6--54
Vector display jitter page 6--55
Distorted vectors in Vector display page 6--55
Control problem page 6--56
Menus horizontally unlocked in Picture display mode page 6--57