Powermac G5 quad 2.5 Ghz power supply failure

Discussion in 'PowerPC Macs' started by hardhatmac, Apr 27, 2009.

  1. hardhatmac macrumors regular


    Jun 13, 2006
    As you can guess from the title, my G5 quad's 1KW power supply died. Apple offered to cover the labor only. They want me to pay the $375 for the new p/s. I'm trying to find a cheaper option.

    I have some computer skillz...not a lot, but some. I could:

    1) do the repair myself (that is if I find a cheap p/s)
    2) have apple do it for $375
    3) find a cheap p/s and still have the local apple store install it (I still need to find a cheap p/s)

    Any advice is welcome.

    Anyone know where to get a cheap 1KW power supply? Or at least know the part number for a G5 2.5 quad late 2005 model?

  2. ScottishCaptain macrumors 6502a

    Oct 4, 2008
    Part number:
    1kW Model: 661-3738

    I can tell you right now that replacing the PSU is no small task. This isn't the same thing as popping out 4 screws on a PC ATX style PSU and unplugging a few cables. The PSU inside the Quad G5 is buried deep in the *bottom* of the case.

    Off the top of my head, you've got to remove the following:
    - Front fan assembly
    - Processor inlet frame
    - Processor Module (the liquid cooling system && processor are a single unit)
    - Processor support bar(s)
    - Heatsink cover
    - Any PCI-Express cards
    - Rear fan assembly
    - PCI card guide
    - Speaker/fan assembly
    - Front panel PCB
    - PCI Divider
    - Logic Board

    Including any and all cables that are attached to the above parts, **JUST** to get to the PSU. You'll also need a good Torx set of drivers. If anything goes wrong, you could potentially fry the entire machine. There is a lot of fine machinery in there, and a procedure of this magnitude is not to be taken lightly.

    To reiterate, you're disassembling the entire machine. Probably a hundred or so screws, of various types, lengths and threads. I would highly recommend that you let a trained Apple tech do this work.

  3. Earl Urly macrumors regular

    Jul 11, 2004
    You can ruin your machine by not putting the processor module in right (you'll take out the processor and the logic board) so maybe it's time to let Apple earn their keep
  4. soldierblue macrumors 6502

    Mar 23, 2009
    If the $375 includes parts and labor, I'd have them do it.
  5. steviec macrumors member

    Apr 25, 2009
    I have the same machine, but the logic board has gone. It has 6.5 GB ram and an upgraded graphics card. I'll sell you mine if interested, that way you can replace the PS and then you would have spare processors, some extra RAM and a spare Graphics Card.

    Email me if interested.
  6. OrangeSVTguy macrumors 601


    Sep 16, 2007
    Northeastern Ohio
    That's a great gesture but you currently don't meet the requirements to sell on this forum.

    Also be warned that the quad 2.5's were also liquid cooled. You should check for any signs of leaks first and if you do decided to change the PSU yourself, be careful not to cause any leaks as you could kill your equipment. Good luck with what ever option you choose to follow.
  7. hardhatmac thread starter macrumors regular


    Jun 13, 2006
    Yup, the $375 is parts and labor.

    I'm still talking to apple support, the last guy I talked to said he was going to talk to his boss to see if he can get me a better deal than 375.

    Thanks for the input guys!
  8. pc297 macrumors newbie

    Sep 26, 2015
    Hi all,

    I can confirm that it is possible to replace the PSU of a quad WITHOUT taking the motherboard out. Here's how:

    1) remove the cpu cover (the metal cover that says G5). It's a bit of a pain as you have to push fown the small plastic rivet that holds it into place
    2) remove front cpu fan
    3) remove front cpu fan adapter
    4) remove pcie cards
    5) remove rear cpu fan
    6) remove the liquid cooling system power cables
    7) remove cpu (see the documentation by ifixit if you're unsure, it's nicely detailed)
    8) remove cpu power cable screws and put the power cables and plastic bits that normallw go underneath the CPU away
    9) remove metal metal CPU holder bar
    10) disconnect PSU motherboard cables
    10) remove PSU cover by unscrewing the 2x 8mm screws on it (one is hidden underneath the CPU "rug" designed to collect any fluid in the case of a leak), you will have to lift the plastic sheet that is glued to the PSU
    11) remove the 4x 8mm screws underneath the powermac case
    12) remove the bottom screw that was used to hold the metal CPU holder bar
    13) remove the 9 round screws holding the PSU to the motherboard
    14) slide the PSU gently towards the front of the computer by one notch or so (so that the round screw holes are offset by 1 notch or so). It won't go any further. You won't damage anything doing that, there are no ICs between those holes and further down.
    15) Sit down with the computer lying flat, and its top facing you. Tilt the PSU towards you as much as you can. It won't come out without using some sort of leverage against the case (it's nearly as if apple planned this so that you have to go to the apple store if removing the motherboard sounds daunting, which it is). You can use a flathead screwdriver to slightly bend the case and force it through. It will come out.
    16) perform the exact reverse operation to fit a new one back in. Take your time to reassemble everything. It works, the one I just repaired using that technique is on next to me at the moment and running cool. Job done, you've saved yourself at least 3-4 hours of work by not having to take the MB out and back in again. Good luck!
  9. Altemose macrumors G3


    Mar 26, 2013
    Elkton, Maryland
    Please understand that this thread is over six years old at this point and Apple will not work on a G5 at all anymore.

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