My Mac Pro doesn't want to get out of bed in the morning

Discussion in 'Mac Pro' started by MotleyPete, Nov 19, 2010.

  1. MotleyPete macrumors regular

    Jun 9, 2008
    I have an early 2008 Mac Pro that has recently developed a startup problem.

    When I press the power button it try's to start up for a few seconds then switches off. After a short wait and a few more attempts it try's harder (fans whirl, sometimes I get a chime, sometimes the Display even turns on) but then it cuts out and turns itself off again. It does this every morning, on several attempts, until after an hour or so it seems to get the message, start up and it'll work fine with no issues for the rest of the day.

    I've tried unplugging all peripherals.
    I've tried a fresh install of Snow Leopard.
    I've tried an SMC reset.
    I've tried zapping the PRAM.
    I've tried removing the internal battery, waiting, then putting it back in.
    I've checked that the RAM is seated properly and there are no red lights.
    I've reset the machine using the internal switch.
    I've pressed the Diagnostic button on the logic board and the LED's report no problems: Trickle power fine, regular power fine (when machine on), no nasty red lights indicating faults on the board, etc.

    So, my guess is that the Power Supply Unit is failing in some way and may need to be replaced. Does anyone else have any thoughts on this? Has anyone had the exact same problem and fixed it with a new PSU?

    I've had the Mac Pro only a couple of years and I'm out of warranty. I also have no Apple Care and would like some input before I splash out some cash (cash that I don't really have)

    Thanks in advance for any input, help and suggestions.
  2. nanofrog macrumors G4

    May 6, 2008
    PSU's going bad, or possibly the logic board. So it looks like you'd be best to carry it in, and have a proper diagnosis done on it (make sure they cover their repairs).

    I wish you luck.
  3. Hellhammer Moderator


    Staff Member

    Dec 10, 2008
    That sounds like me in the morning :p Anyway, Nano is probably right, either PSU or logic board. You could try plugging it into another power socket (possibly in different location), just to rule out an issue with certain power socket
  4. MotleyPete thread starter macrumors regular

    Jun 9, 2008
    Thanks for your input guys. I've tried different power sockets in the house, but to no avail.

    I think a failing PSU is the most likely culprit and I've managed to order a new one at a fairly reasonable price, so hopefully that'll sort things out for me.
  5. biggd macrumors 6502


    Apr 6, 2008
    I promise its the power supply
  6. MotleyPete thread starter macrumors regular

    Jun 9, 2008
    New PSU arrived, plugged it in, startup, bong, launch, Finder, all systems go.

    I'll post here again if it starts acting up, but if not then anyone finding this thread will have a good idea what a PSU failure looks like.


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