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Operational Problems
Table 3-12 Operational Problems - Display
Symptom
No response - all white or all black.
Display is blank but backlight works.
Backlight doesn't light in dark ambi-
ent conditions.
Contrast does not adjust for ambient
temperature.
Fails Display Test in Diagnostic
Mode (display problem other then
symptoms above).
Fails Display Test in Diagnostic
Mode (ambient light readings).
Fails Display Test in Diagnostic
Mode (backlight).
3-26
Display
The following table covers problems that might arise with the LCD display.
Before replacing any parts, check to see if the cables and flex circuits are
properly connected. See "Servicing Notes" on page 4-1.
Possible Causes
Contrast misadjusted.
Control PCA failure.
Display failure.
Bad connections involving Display
Data Cable.
Display failure.
Control PCA failure.
• Display failure.
• Control PCA failure.
• Ambient light sensor failure.
Display failure.
Control PCA failure.
Display failure.
Control PCA failure.
Control PCA failure.
Interface PCA failure.
Display failure.
Control PCA failure.
Suggested solution
Adjust contrast.
Replace Control PCA.
Replace Display.
1. Check/reseat data cable.
2. Replace data cable
Replace Display.
Replace Control PCA.
Diagnose as follows:
In Diagnostic Mode, run Display
BACKLIGHT ON
Test and press
BACKLIGHT OFF
softkeys.
• Backlight does not respond:
Replace 1) Display 2) Control
PCA.
• Backlight responds normally:
test Ambient Light Sensor
(below).
In Diagnostic Mode, run Display
Test and check ambient light read-
ings.
• Normal: Replace 1) Display 2)
Control PCA.
• Abnormal or not responding:
Replace 1) Control PCA 2)
Interface PCA.
Replace Display.
Replace Control PCA.
Replace Display.
Replace Control PCA.
Replace Control PCA.
Replace Interface PCA.
Replace Display.
Replace Control PCA.
Troubleshooting
and
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