Quad Issues

Discussion in 'PowerPC Macs' started by bunnspecial, Jun 17, 2015.

  1. bunnspecial macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #1
    I mentioned this last week, but I pulled the processor cards on my Quad late last week to repaste the CPUs.

    Since then, I have not been able to get it to boot.

    Reading the LEDs on the logic board, and following the service manual, it looks like everything more or less proceeds normally within the first few seconds of power-up. There are initially no lights on, and LED 7 flashes momentarily(as per the service manual, this is normal). A few seconds later, LED 2, indicating CPU overtemperature, will come on and stay on.

    I've pulled the cards again and verified that they are in solid contact with the water blocks then(again) cleaned and repasted both the blocks and the CPU dies. I have the hex-head spring loaded screws snug, so the contact between the blocks and the CPU should be good.

    The LCS has no leaks and I can hear the pump running when the system is powered on. All fans are also running. I do have the air deflector in place when all of this happens.

    Does anyone have any thoughts on what could be going on?
     
  2. Goftrey macrumors 68000

    Goftrey

    Joined:
    May 20, 2011
    Location:
    Wales, UK
    #2
    Grab a magnifying glass and take a look at the pins on both the daughter cards & the motherboard itself. They are extremely fragile and it's very easy to bend even just one of them ever so slightly out of place.
     
  3. Altemose macrumors G3

    Altemose

    Joined:
    Mar 26, 2013
    Location:
    Elkton, Maryland
    #3
    Try swapping the CPUs out for one another. For example, put CPU 1 where CPU 2 is.
     
  4. RedCroissant Suspended

    Joined:
    Aug 13, 2011
    #4
    I could be crazy here, but isn't it a necessity to recalibrate the system after upgrading/modifying the CPUs? I know that you simply replaced the CPUs but that might have been enough to cause issues.
     
  5. Altemose macrumors G3

    Altemose

    Joined:
    Mar 26, 2013
    Location:
    Elkton, Maryland
    #5
    @RedCroissant Yes. Whenever the CPUs are removed from a G5 then the cooling system should be re-calibrated. That being said, a G5 should run without calibration but with the fans at full blast. The fact that bunnspecial's G5 is not booting at all indicates an underlying issue.
     
  6. bunnspecial thread starter macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #6
    On a whim, I bought a complete LCS/CPU assembly from Ebay.

    It dropped right in, and I'm happy to report that I'm typing this message from the Quad now.

    I haven't run thermal calibration yet, but the fans are running at what I would consider "normal" speeds and temps look good. I might run it tomorrow, but for the time being I'm happy.
     
  7. Altemose macrumors G3

    Altemose

    Joined:
    Mar 26, 2013
    Location:
    Elkton, Maryland
    #7
    @bunnspecial I bet you accidentally fractured the CPU card during removal and installation. That is exactly what I did with one of my 1.8 GHz CPUs.
     

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