Nokia rx-34 Service Manual

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Nokia rx-34 Service Manual Manual pdf 134 page image

Display module troubleshootingGeneral instructions for display troubleshootingThe first step is to verify with a working display that the fault is not on the display module itself. The displaymodule cannot be repaired.The second step is to check that the engine is working normally. This can be done by connecting the phoneto a docking station and starting Phoenix service software. With the help of Phoenix read the phoneinformation to check that also the application engine is functioning normally (you should be able to read theAPE ID).After these checks proceed to the display troubleshooting flowcharts. Use the Display Test tool in Phoenix tofind the detailed fault mode.Pixel defectsTable 8 Display module troubleshooting casesDisplay blank There is no image on the display. The display looksthe same when the phone is on as it does when thephone is off. The backlight can be on in some cases.Image on the display not correct Image on the display can be corrupted or a part ofthe image can be missing. If a part of the image ismissing, change the display module. If the image isotherwise corrupted, follow the appropriatetroubleshooting diagram.Backlight dim or not working at all Backlight LED components are inside the displaymodule. Backlight failure can also be in theconnector or in the backlight power source in themain engine of the phone. Backlight is alsocontrolled automatically by the ambient lightsensor.This means that in case the display is working(image OK), the backlight is faulty.Visual defects (pixel) Pixel defects can be checked by controlling thedisplay with Phoenix. Use both colours, black andwhite, on a full screen.The display may have some random pixel defectsthat are acceptable for this type of display. Thecriteria when pixel defects are regarded as a displayfailure, resulting in a replacement of the display, arepresented the following table.Table 9 Pixel defectsBright sub-pixels (sometimes called on-pixels or stuck-on) arecharacterized by the appearance of bright/coloredpixels in, for example, black full screen picture.RX-34BB Troubleshooting and Manual Tuning GuidePage 6 –26 COMPANY CONFIDENTIAL Issue 2Copyright © 2007 Nokia. All rights reserved.