Display Module Troubleshooting; General Instructions For Display Troubleshooting; Table 1 Display Module Troubleshooting Cases; Table 2 Pixel Defects - Nokia 301 Service Manual

Display module troubleshooting

General instructions for display troubleshooting

Context
• The display is in a normal mode when the phone is in active use.
• Display is in a sleep mode when the phone is in idle mode.
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
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Table 1 Display module troubleshooting cases

Table 2 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.
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BB Troubleshooting and Manual Tuning Guide
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.
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 Nokia Care Suite PST. 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
RM-839; RM-840; RM-841
Black dot Total
defect
1 1
Issue 1