2007 Mac Pro 8 core, might need new motherboard

Discussion in 'Mac Pro' started by Vigvetteman, Jan 8, 2011.

  1. Vigvetteman macrumors newbie

    Jan 8, 2011
    So Cal
    Ready to pull my hair out over this....
    ( and thanks for any help offered in advance )

    Long time Mac lover, user & tinkerer.

    I have a Mac Pro 8 core 3.0ghz ( A-1186 )
    Inten Xeon 5365 CPU's
    The build date Aug 7 2006
    The motherboard sticker 630-7951
    2.1 vers.
    Purchased used,last month, has not run correctly yet.
    This was going to replace my G5 2.3 dual.

    This Mac looks like is was in front of where the owners would dump out their
    vacuum cleaner... so I went inside and cleaned EVERYTHING.
    and put new Arctic silver on the CPU's.

    The machine boots off the hard drive or a boot disc.
    I'll get all the way up and can start using the machine for a limited amount
    of time.then black screen , boot chime & restart. and the more " load " ( read game or something processor intensive ) causes it to restart faster.

    While running looking at the motherboard diagnostic lights
    The GPU light goes away.and the EFI GO blinks off.
    The machine shuts down & restarts right back up......

    Im stripped down to 2GB of memory ( 2 1GB sticks ) in the bottom..
    This cycle takes about 7 minutes when the machine is " cranky ".
    And it's random... last night I ran for 2 hrs with NO ISSUES...
    this am .. back to the 7 minute thing.
    On restart..
    Trickle on..
    Power on..
    Then the EFI GD.. goes on & stays on
    Then the GPU light comes on..
    ( the gray Apple screen and the spinning gray " gear " icon )
    Get to blue screen
    Get to desktop
    GPU light blinks~
    EFI blinks~
    commence restart...

    I have tried the following
    Measured power supply 4.96 & 12.05
    Reseated EVERY connector
    Reset the PRAM
    SMC reset
    PMU reset
    New battery
    Brand new Apple video card
    Tried 2 KNOW working DIMM holder cards & know memory.
    Sacrificed a goat & chicken as a last ditch effort.

    But then I called Apple support.. ( which confused me more ).
    They state the following...
    I have the Ram installed incorrectly..
    Each of the matched pair should be 1 single stick in the upper 1 single stick in the lower. ( the machine will not boot in this config ).

    NOR will it boot with a pair in the top AND bottom cards..
    But either card , one at a time in either slot will boot.

    It will not make it through apple hardware test.
    And at this point I think I have a memory controller issue
    So I guess my motherboard is gone...
    We love Mac's states I need a 661-4307-R for a replacement


  2. markdz macrumors newbie

    Sep 26, 2011
    2007 Mac Pro 8 core, might need new motherboard

    Just curious as this has happened to me on the same system, did you ever get the mother board? If so, how is your system now?

  3. Vigvetteman thread starter macrumors newbie

    Jan 8, 2011
    So Cal
    New motherboard was the trick

    been running FLAWLESS for quite some time!

  4. carlish, Dec 4, 2015
    Last edited: Dec 4, 2015

    carlish macrumors newbie


    Sep 2, 2015
    So you replaced the Logic Board at the end. Which replacement?
    I'm running the same problem and I found an old 661-4307 Logic board (EEE=X7Q like my 630-7951) tu use for an acceptable price (as a used one)

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