12" white iBook G4 display repair problem

Discussion in 'PowerPC Macs' started by Bryan.C, Apr 2, 2009.

  1. Bryan.C macrumors newbie

    Apr 1, 2009
    This is a cry for help: I replaced the broken display/hinge/frame on a G4 laptop that was dropped but otherwise running okay. Now the screen is dark & dim; same as if the inverter was unplugged.

    Wires & connectors look okay, continuity is okay where ever I checked. I methodically swapped the video cable, inverter cable, inverter board, lcd panel from a G3 (that has a bad logic board). I've wiggled and jiggled and tapped and the display stays dark. OS & apps are all running in the dark. Brightness function keys are functional. Software brightness control is functional. Battery charges. At startup, CD and hard drive spin up as expected.

    Reed switch still "sleeps" and "wakes." [ The cooling fan might hold a clue: about half way through my troubleshooting I noticed that the fan fails to function except for three seconds when I open the lid and the sleeping laptop wakes up... just as though the fan were unplugged except when it wakes from sleep; otherwise the fan doesn't fan. ]

    Assuming that the inverter board that I used to troubleshoot is a known good one, what am I missing? Logically, it would be the logic board but I can't afford to replace it. It isn't my laptop. I am the one who tripped over the powercord; breaking the hinge. I need to fix it. I'm going to try to find another used inverter board.

    Any ideas?

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