Display Module Troubleshooting; General Instructions For Display Troubleshooting - Nokia 500 Service Manual

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BB Troubleshooting and Manual Tuning Guide

Display module troubleshooting

General instructions for display troubleshooting

The first step is to verify with a working display that the fault is not on the display module itself. The display
module cannot be repaired.
Note: Always use the display with the phone's window while checking the display's visual
functionality.
The second step is to check that the engine is working normally. This can be done by connecting the phone
to a docking station and starting Phoenix service software. With the help of Phoenix read the phone
information to check that also the application engine is functioning normally (you should be able to read the
APE ID).
After these checks proceed to the display troubleshooting flowcharts. Use the Display Test tool in Phoenix to
find the detailed fault mode.
Pixel defects
Display blank
Image on the display not correct
Visual defects (pixel)
Bright sub-pixels
Dark sub-pixels
Combined sub-pixel
Issue 1
Table 5 Display module troubleshooting cases
Table 6 Pixel defects
COMPANY CONFIDENTIAL
Copyright © 2011 Nokia. All rights reserved.
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.
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.
Pixel defects can be checked by controlling the
display with Phoenix. Use both colors, black and
white, on a full screen. R, G, B are also helpful.
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 in the following table.
(sometimes called on-pixels or stuck-on) are
characterized by the appearance of bright/colored
pixels in, for example, black full screen picture.
(sometimes called off-pixels, stuck-off, or black
pixels) are characterized by the appearance of dark
pixels in white, red, green, or blue full-screen
picture.
defects are characterized by at least two sub-pixels
defects (bright or dim) being closer than 5 mm to
each other.
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