PowerBook G4 won't boot

Discussion in 'PowerPC Macs' started by max¥¥, Nov 7, 2012.

  1. max¥¥ macrumors 6502a

    Aug 7, 2008
    Over there....
    So i have a 1.5ghz 12" powerbook G4 that i got to use at school, it was all working ok untill i took it on a school trip to italy a few days ago. I left it on charge and sleeping one day and when i came back to it it was utterly dead, pulled the battery and reset the pmu, nothing, so i let it sit for a day and it booted. but not for long. about 30 secs after the os loaded the keyboard would stop working, so i rebooted it an we where back at square 1. let it sit another day and it worked again, but same deal, keyboard stopped working 30 seconds after boot and it died when i tried to reboot. left it another day, as soon as i powerd it on i jumped into open firmware and ran: reset-nvram then reset-all. this seemed to fix it, was working normally again. we get on the plane back and guess what. same thing. not responsive to the power button at all. when i got home i took it apart intending to replace the pram battery but of corse it is a super capicitor that is soldered to the logicboard. left it a day and now i am still not getting anything.

    so anyone have any idea how to fix it? it is worth replaceing the super capicitor? (i am pretty good at soldering)

  2. 666sheep macrumors 68040


    Dec 7, 2009
    If you'll get right capacitor and you're good in soldering you can try to replace it. I couldn't be worse than now. But judging by symptoms, I have feeling that your problem is the PMU itself. If you have logic board removed see if there are any signs of burnt traces or SMD components. Use magnifying glass.
  3. yamu macrumors newbie

    May 12, 2011
    Maybe the powerbook gets false sleep signals from a defective hall-effect-sensor board. a small board at the side of the dvd drive connected to the dc-to-dc board. simply unplug it and see if it working normally other than the deactivated sleep function when closing the lid.
  4. seveej macrumors 6502a


    Dec 14, 2009
    Helsinki, Finland
    At least in some models, you can test the functionality of the hall sensor
    Use the guide given at http://mrob.com/pub/ibook.html to create your diagnostic.

    That said, have you tried taking out all memory chips?
    Can you go to the console and see what kind of things go into the system log just before the machine "shuts down"?

  5. max¥¥ thread starter macrumors 6502a

    Aug 7, 2008
    Over there....
    I ended up buying a new logic board (since i need this laptop, so my parents decided to pay the £40 it cost for a new logicboard) but i may try swapping the cap when i pull the board out to replace it

    I did try disconnecting it when i had it open yesterday with no change, so seems the logicboard is screwed

    Unfortunatley as i can't as it won't boot at all

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