Nokia RM-70 Service Manual page 125

RM-70
BB Troubleshooting and Manual Tuning Guide
• The operating modes of the display can be controlled with the help of
Display blank
Image on the display not correct
Backlight dim or not working at all
Visual defects (pixel)
Item
1 Defect
counts
2 Combined
defect
counts
Steps
1. Verify with a working display that the fault is not on the display module itself.
The display module cannot be repaired.
2. Check that the cellular engine is working normally.
i To check the functionality, connect the phone to a docking station.
Phoenix service software.
ii Start
Issue 1
Table 9 Display module troubleshooting cases
Table 10 Pixel defects
White dot defect
R G
1 1
Not allowed.
Two single dot defects that are within 5 mm of each other should be interpreted
as combined dot defect.
COMPANY CONFIDENTIAL
Copyright © 2005 Nokia. All rights reserved.
Phoenix .
There is no image on the display. The display looks
the same when the phone is on as it does when the
phone is off. The backlight can be on in some cases.
Image on the display can be corrupted or a part of
the image can be missing. If a part of the image is
missing, change the display module. If the image is
otherwise corrupted, follow the appropriate
troubleshooting diagram.
Backlight LED components are inside the display
module. Backlight failure can also be in the
connector or in the backlight power source in the
main engine of the phone. Backlight is also
controlled automatically by the ambient light
sensor.
This means that in case the display is working
(image OK), the backlight is faulty.
Pixel defects can be checked by controlling the
display with Phoenix. Use both colours, black and
white, on a full screen.
The display may have some random pixel defects
that are acceptable for this type of display. The
criteria when pixel defects are regarded as a display
failure, resulting in a replacement of the display, are
presented the following table.
B White Dot
Total
1 1
Nokia Customer Care
Black dot Total
defect
1 1
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