iBook G4 only runs w external display

Discussion in 'PowerPC Macs' started by JohanVild, Apr 10, 2007.

  1. JohanVild macrumors newbie

    Mar 20, 2004
    I picked up this iBook G4 12" 1.07 from a friend of mine as an organ donor for my PB 12"(switched the LCDs) It had a dead hard drive in it and I supposed it was suffering from the logic board problems, but the screen lights up and stays in grey. It will hook up to a VGA screen and runs fine with that. My question is: if it was indeed the video chip that was unseated would it display on the VGA at all? Is this a cable problem? Could it just be the cable running from the logicboard to the display that is chewed up(possibly in the hinge area)?
    I popped it open and tried to see if the connector on the logic board was loose, but that didn't help.
    Anybody had this problem?
  2. JohanVild thread starter macrumors newbie

    Mar 20, 2004

    So essentially my question is: can I get this bad boy up and running again or should I chuck it?
    It just seems to me that it is not the typical video card issue, but don't know enough about it to make the call.
    Anybody have an idea?
  3. techound1 macrumors 68000


    Mar 3, 2006
    The general rule of thumb is that if you can consistently run external video, you do NOT have the logic board video death (and the backlight wouldn't work).

    If it lights up and stays gray, your backlight is working but the cable that sends information to the screen (or its connection on the logic board) is not. 98% of the time it's a cable problem from the board to the back of the lcd (pinched, pulled, or otherwise mangled). The other 2% of the time it's the actual connector on the board and you're SOL for portability.
  4. JohanVild thread starter macrumors newbie

    Mar 20, 2004
    Great - thanks.
    I guess I'll try to save it from the landfills then.
  5. JohanVild thread starter macrumors newbie

    Mar 20, 2004
    Still no signal

    So I replaced the display cable and put it back together. Still no signal coming up on the lcd. It still comes on brightly - but grey. Could it be the inverter board or does this mean for sure that the connector on the logic board is bad?
    When I boot in target mode it mounts to my other computer but the firewire/target screen with the bouncing logo doesn't come up on neither screen (built-in LCD or external VGA) - don't know if that tells anybody anything.
    Appreciate any input - thanks!

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