Powermac G5 Fix

Discussion in 'PowerPC Macs' started by efcjimbo, Oct 13, 2009.

  1. efcjimbo macrumors newbie

    Apr 21, 2008
    Heres the problem

    Powermac G5 1.8 Dual, running well for 5 years.
    Had a loud crack sound like a CD case breaking.
    Machine goes off, no light when pushing power button there after.
    The crack sound happened after pulling out firewire pocket drive from the front firewire port.

    Do you think with these symptoms = Power supply
    Does a power supply fault make a crack sound?
    Could a new a power supply unit fix my problems?

    I could take a risk and buy a Power supply unit for £100, I could probably manage to install myself.
    Getting it fixed by an Apple engineer with parts and labour would cost more than its worth.

    Also what the odds some other part would be messed?
    I know the harddrive is working OK.
  2. Sun Baked macrumors G5

    Sun Baked

    May 19, 2002
    Capacitors and other electronic parts occasionally short out, along with dust amongst other parts of the machine causing a short.

    Likely if you had a simple volt/resistance meter, there would likely be a simple test for checking out the power supply... Looking at voltage, and for a closed circuit across a couple pins. What are good values for the supply and where to find them, have no idea.


    Likely, you'd want to pull the HD, and do any further testing with it out of the machine ... just to make sure a problem doesn't kill that. Can always boot from the CD drive.
  3. leighonigar macrumors 6502a

    May 5, 2007
    Could be the PSU, might just be the fuse in the PSU. There are instructions out there on these PSUs. I believe you can hack a PC PSU in if you don't need the ADC port power.
  4. MacModMachine macrumors 68020


    Apr 3, 2009
    the problem is the firewire port is most likely broken,

    motherboards/logic boards have fuses on them that the bios/smc/pmu can check for all usb/firewire ports,

    if this fuse is tripped it WILL NOT start, you must unplug the firewire cable from the logic board, your computer should then restart.
  5. OrangeSVTguy macrumors 601


    Sep 16, 2007
    Northeastern Ohio
    I've heard of this problem in the G5s. I remember it being the front power button board. It would "spark" every time you pressed the button as there was a short to the aluminum casing or something similar. Since you did say you removed the firewire from the front, it's all connected to the same board so you possibly shorted something out from the movement.

    Could just be a $10 fix compared to $100, also a lot easier as the removal of the G5 power supply can be difficult for some people.
  6. efcjimbo thread starter macrumors newbie

    Apr 21, 2008
    I haven't disconnected the rear firewire port just yet as I looks like I need to take apart the machine to get to the connection to logic board.

    But the front firewire port seems to be 1 connection to the logic board, bundled up with the power button, usb, & headphones.

    Does this mean I would need a new power button/firewire/usb/headphones unit?
    In order to disconnect the firewire.

    If so, what is this part called, If I was buying one? and if the front firewire is broke do I need to also remove the rear firewire ports too?

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