Mac Pro 3,1 won't boot - diagnosis? Graphics card?

Discussion in 'Mac Pro' started by doobydoooby, Oct 6, 2013.

  1. doobydoooby macrumors newbie

    Joined:
    Oct 17, 2011
    Location:
    Genève, Switzerland
    #1
    Hi,

    I'm hoping maybe someone might be able to help me diagnose my poorly Mac Pro 2008 3,1....

    All was working fine until upon waking from sleep the screen showed a black screen with only the mouse pointer displayed, and then a forced reboot started. And of course the reboot won't complete. I hear the chime at the beginning so theoretically the hardware check is ok. I have removed all the external peripherals except wired keyboard and mouse and one screen. None of the traditional approaches will get it going; I get as far as the white apple screen, the little booting clock starts to move around for a second or so and then hangs, then the system tries to boot again. The white boot screen is consistently garbled with a patchwork of pink or yellow blocks all over the screen.

    Cmd-r doesn't work at all, if I hold down the option key I can see the original hard drive, the 10.8 recovery partition and the time machine drive but selecting any of them doesn't change the fact that I can't get anywhere- selecting the recovery partition makes no impact at all.

    I have tried going into efi and checking the main boot hard drive which returns no errors. I have tried resetting the pram.

    Booting in safe mode doesn't work, it hangs half way and the point at which the hang occurs doesn't really give any hints to the cause if I look at it in verbose mode. The only clue I have is that booting in safe mode still gives the garbled screen colouring. I'm inclined to think it must be the graphics card, it just seems a bit strange that I get the startup chime which I thought indicated hardware was all good. It's running the original gt8800 card.

    If the startup boot begins general advice on the Internet seems to suggest a software rather than hardware problem, but given I'm getting the same unresponsive result even when selecting the recovery partition I'm guessing the graphics card is stressed.

    Any ideas? All comments gratefully received! Many thanks in advance...
     
  2. pastrychef macrumors 601

    pastrychef

    Joined:
    Sep 15, 2006
    Location:
    New York City, NY
    #2
    You mentioned "garbled screen colouring", would it be possible to take a photo of this and show us? It "sounds" like a video card that's on the brink, but a picture would help in making a more definitive diagnosis.

    Are the recovery partition and main boot partition on the same drive?
     
  3. DanielCoffey macrumors 65816

    DanielCoffey

    Joined:
    Nov 15, 2010
    Location:
    Edinburgh, UK
    #3
    Since it is an 8800, you might be able to get a little longer out of it by googling "bake 8800gt".

    If you can get the card going again, make sure your backup is fully up to date and make a serious effort to find or buy a replacement card urgently.
     
  4. doobydoooby thread starter macrumors newbie

    Joined:
    Oct 17, 2011
    Location:
    Genève, Switzerland
    #4
    Thanks for your responses.

    Given the lack of an alternative it's tricky for me to post a picture to the web but basically I get a relatively normal screen in that whatever is supposed to be on the screen can be seen, with a messed up overlay of random colors. So if I boot in safe verbose mode I have a black screen with fully legible writing, in the black ground lots of blue rectangular blocks down the screen; if I let the normal boot try to begin then I get a fairly white screen, the grey apple logo and countdown clock beginning, and the whole thing is overplayed in random places with link or yellow blocks.

    ----------

    The main drive and recovery drive are on the same HD but then I have a separate time machine drive with a bootable partition; none will boot which makes me think it must be hardware rather than software. I'm just confused that the computer would chime to begin as I thought that meant the hardware check was fine...

    Will look up baking a 880gt and see what comes up!
     
  5. 666sheep macrumors 68040

    666sheep

    Joined:
    Dec 7, 2009
    Location:
    Poland
    #5
    It's the card, symptoms are clear. Baking could extend its life by few days, weeks or months (at best). But the problem will be back.
     
  6. pastrychef macrumors 601

    pastrychef

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    Sep 15, 2006
    Location:
    New York City, NY
  7. DanielCoffey macrumors 65816

    DanielCoffey

    Joined:
    Nov 15, 2010
    Location:
    Edinburgh, UK
    #7
    Try the baking trick then - you have nothing to lose.
     
  8. doobydoooby thread starter macrumors newbie

    Joined:
    Oct 17, 2011
    Location:
    Genève, Switzerland
    #8
    Many thanks to all and esp to Daniel for suggesting the ridiculous baking graphics card. I don't know what witchcraft this is, but 200 degrees for ten minutes and my computer is working again! Hilarious. You people are stars.
     
  9. DanielCoffey macrumors 65816

    DanielCoffey

    Joined:
    Nov 15, 2010
    Location:
    Edinburgh, UK
    #9
    Great to hear it, but you now NEED to replace the card. At least you have a small window in which to do so.
     
  10. Gav Mack macrumors 68020

    Gav Mack

    Joined:
    Jun 15, 2008
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    #10
    Not necessarily, I've baked about a dozen nvidia gpus on PCIe and as long as you use decent thermal paste such as artic silver and replace the 1mm thermal pads with cut to fit Phobya pads the earliest I know are still working fine nearly 3 years later. Don't sit the card in the oven upside down gpu must be on top and let heat and gravity do its trick for 10 mins precisely at 200c then switch off oven crack open the door and let it cool slowly for an hour or two before moving it. I've even baked duff nvidia gpus on G40 hp laptop mobos but only cooked for 5 minutes to stop other components melting though I added a few copper coins stacked on top of the gpu to give gravity a hand!
     
  11. doobydoooby thread starter macrumors newbie

    Joined:
    Oct 17, 2011
    Location:
    Genève, Switzerland
    #11
    Well on the basis that I don't like to find myself unexpectedly with a bust 'pooter, since it's never ever going to be convenient, I replaced the 8800gt with a gtx660 PC Card which is excellent value and am v impressed with that. A doddle to install and absolutely silent in comparison with the 8800gt which was after all 5 1/2 years old. I will keep the 8800 in reserve just in case I ever have a different problem and need to access the boot screen.

    I reckon the Mac Pro isn't too happy at being allowed to sleep and wake on a regular basis. The only things that I have ever had go wrong with it, a hard drive failure and now the graphics card, both happened the second the mac came back up from sleep. It might just be coincidence but I'm kinda inclined to avoid sleep from now on especially since the fault in the 8800gt was clearly created by expanding and contracting solder.
     
  12. Gav Mack macrumors 68020

    Gav Mack

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    #12
    Gas mark 6 and odds on you'll have a functional backup :D

    [​IMG]
     
  13. MacVidCards Suspended

    Joined:
    Nov 17, 2008
    Location:
    Hollywood, CA
    #13
    More tips for the Betty Crockers in the audience:

    1. Set a timer. I do 9 minutes at 375-400 F. If you forget and let them go too long, the components on the backside of card start falling off like rain. Then it is landfill time. Also, the caps on the front will start popping like evil, stinky firecrackers. They will continue spurting out nasty goo for a few moments.

    2. Either wear a gas mask or make a point to NOT BREATHE while pulling from oven. The smell being awful is a good sign that you shouldn't breathe it in. I hold my breath, pull the sheet it is on and gingerly place under the hood on the range. Run the fan and leave room. NOW you can breathe again. Let all the nasties out gas for awhile.

    3. BE EXTREMELY careful during disassembly and reassembly phases. It is crucial to lay the fan perfectly flat on a table top but LET THE BRACKET HANG OVER THE EDGE. Otherwise you are flexing the card with each push on screwdriver. The whole issue is with fragile solder joints between the square metal GPU chip and the hundreds of little solder balls linking it to the PCB. The PCB can bend, the GPU is more rigid. So any flex between them can easily re-fracture the same solder balls that you just fixed.

    4. As a general rule, cards that show screen artifacts have a good (50-75%) chance of resurrection. Cards that don't boot at all are FAR less likely to make a recovery (10%)

    When 8800GTs were in demand we ended up with at least 100 that died in our possession. I would wait until we had at least 10 or 12 before we had a "baking day". We usually had about 50% come back to life. If they didn't come back after 2 bakings, they weren't coming back. It is an awesome feeling to bring a "garbage" card back into the land of the living.

    BTW, 7300GTs can also respond to this. But be sure it isn't the "bulging capacitor" issue as those don't get helped by baking.
     
  14. Gav Mack macrumors 68020

    Gav Mack

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    #14
    I'm not surprised choking on a dozen of them lol.

    Washing and blowing air to remove debris carefully pre bake cuts down the smell.

    Cracking the oven half open and leaving them for 60-90 mins to let them thoroughly cool undisturbed full stop. Advice from a mate who's probably done more solder work than this whole forum that I've heeded and seems to work.

    Place card on chopping board topped with anti static sponge to reassemble.

    The perfect kitchen computer repair methinks and not when the missus and kids are around :D
     
  15. banjogilbert macrumors newbie

    Joined:
    Aug 12, 2015
    #15
     
  16. OS6-OSX macrumors 6502a

    OS6-OSX

    Joined:
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    Location:
    California
    #16
    "Baking?" Now you tell me! I thought cooking them anyway would work! :p
    8800gt.png
     
  17. MacVidCards Suspended

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