G4 MDD Unique booting issue

Discussion in 'PowerPC Macs' started by EngramAgility, Jun 30, 2009.

  1. EngramAgility macrumors newbie

    Jun 11, 2009
    So I have searched the internets for a problem like mine, but haven't come across it.

    I last started my computer in August of 2008 (bought a MBP) and now am trying to sell this one and had a large problem:

    I plugged it in, all the peripherals and everything and booted, the light came on, the power supply fan went on and then the obscenely loud cooling fan came on but nothing came up on the display. I thought it was a display issue and checked and replaced all the cables and used a different display.

    Now when i turn it on the power supply fan comes on, the main fan comes on but no light. the light comes on when i press and hold it but as soon as it is released it fades out. the little red light on the motherboard is on however

    I took out all my PCI cards and unplugged everything from the mac, i followed instructions on apple.com to reset that button on the motherboard. Im not sure what else to do.

    I would put specs up here but i have no idea what they are, haven't used this computer in years.
  2. Dave H macrumors 6502

    Dave H

    Mar 2, 2008
    Have you tried a PMU reset?

    It also might need a new PRAM battery.
  3. EngramAgility thread starter macrumors newbie

    Jun 11, 2009
  4. kellen macrumors 68020


    Aug 11, 2006
    Seattle, WA
    Battling the same thing. Seems like half of people have it fixed with a new battery, others with a new power supply.

    I fixed mine by buying a EOL Mac Pro.

    If you find out a fix, please post here.

    To get it to boot for a quick fix that won't stay working, unplug it from the wall for a good hour. That seems to let it boot once and then you have to repeat to get it to boot again.

    Best of luck.
  5. Halethorpe macrumors newbie

    Apr 30, 2008
    Just had this problem.

    I have a 1.25 MDD Windtunnel. I am the original owner, and it's seven years old now.

    I just recently had this problem. The screen just went black. I thought it was the video card. I restarted to no avail, . . . at first, but it eventually came back. Soon, it died again.
    I called a nearby Mac repair service seeing if they could help me with a card. After a quick consultation, they came back :"It sounds like bad RAM."
    I had added another gig of after-market, so this sounded plausible. It took two weeks of pulling and replacing modules, but eventually I found the culprit. It was one of the Apple originals.
    I had the red light light and all.

    Good luck.
  6. Keniff macrumors 6502a


    Dec 21, 2008
    United Kingdom
    Try this procedure below it may fix your problem:

    1) Unplug the tower from the wall.

    2) Open the side and locate the battery on the motherboard that folds out in front of you; it's a 1/2 length AA and is the only thing that looks anything like a battery on there.
    Removing it should be pretty obvious.

    3) Push the power button on the front of the computer.
    This is to drain any power left in the computer; the button will probably light up briefly; this is normal.

    4) Leave it sitting there for at least 10 minutes.
    I've heard of people having luck with 24 hours instead of a few minutes, but I'm skeptical that'll make any difference so long as you press the power button after unplugging it.

    5) Put the battery back in the same direction you removed it.

    6) Push the CUDA button; this Apple Support document explains:

    7) Plug it back in, turn it on, (and hope for the best) :)

    It's also possible that replacing that battery could help; the computer will usually work even if it's dead (although the clock will be reset if you ever unplug it), but I've seen some that just plain refuse to start when it's dead. You can find them at most electrical shops.
    Google will help you find the exact one, or you can just take it in somewhere and find one with the same size and voltage.

    I hope this helps?

  7. Halethorpe macrumors newbie

    Apr 30, 2008
    Dead screen problem

    I hope I made it clear.
    My problem was caused by a bad RAM module.
    Shut-down, pull a module, and re-start. Do that until you find the right one. If it displays that behavior again after it was fixed, you just pulled the wrong module. Start over.

    P.S. Sometimes the RAM cradles get dirty or corroded. You may just have to void a position, or find a method for cleaning.
  8. EngramAgility thread starter macrumors newbie

    Jun 11, 2009
    Thanks for the help everybody! I really appreciate it. I am trying out all of your suggestions. Will update with the results later!:)
  9. EngramAgility thread starter macrumors newbie

    Jun 11, 2009
    Just in case anybody looks back at this thread for information, I never replaced the power supply on the tower and for now it is just sitting in my office unused :(

    If I ever get around to fixing the problem, I will try to remember to post here.

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