Mac Pro logic board misdiagnosis

Discussion in 'Mac Pro' started by realchriscasey, Oct 24, 2011.

  1. realchriscasey macrumors newbie

    Oct 24, 2011

    My family has a Mac Pro 1,1. It was purchased with a 7300 GT, but later upgraded to an 8800. A couple of weeks ago, the machine shut itself down while in use. At the time, it was booted into Windows via Bootcamp, and was being used to play a video game. The system could no longer be booted into Leopard (kernel panic), and when booted in windows exhibited extremely poor video issues (low resolution, low color.)

    We brought the machine to an Apple Store immediately. They couldn't immediately identify the cause of the failure, so they sent it to their "secret underground support dungeon." They called to let us know that they thought it was a video issue, and were waiting on a replacement card to confirm it. This was in-line with my guess, since the machine booted fine but had some crippling graphical issues.

    It took over a week to hear from them again. The diagnosis: logic board failure, $700 to fix. The amount of time it took them to get back to us on this left me a bit suspicious, so we took the machine home still in its broken state, and tried replacing the video card ourselves. We slipped in the original 7300, and the machine booted into Windows just fine. We are still unable to boot Leopard: we get the apple logo, the spinner, and eventually (after 15 minutes), the light blue boot screen. The spinner continues to appear and disappear every minute or so, but the system never comes up.

    So, the question to y'all is this: how do we get our mac back? Apple support really has been counter-productive in getting our machine back. It felt like the $700 price tag was to get us to go away or buy a new Pro. I'm happy to purchase a new 5770, Snow Leopard / Lion, a new HD, or whatever combination of these that we need to to get this thing running again. Any advice would be much appreciated.

    Thanks much!
  2. Intell macrumors P6


    Jan 24, 2010
    Have you tried to reinstall Leopard using the 7300 card?
  3. scotttaylor macrumors newbie

    Aug 15, 2010
    My MacPro 3,1 died awhile back and it was misdiagnosed by Apple. In my case it was a defective video card and Apple initially told me it was the logic board and/or both CPU's and would be $2800 to fix.

    I ended up pulling the video card out of the machine and booting it headless. You can still screen share or file share with a headless Mac. This let me quickly identify the video card as the problem.

    In the end, Apple redeemed themselves and gave me a free ATI 4870...

    Good luck!
  4. amgems macrumors newbie


    Feb 2, 2008
    I have an early 2008 Mac Pro.
    It started out that I would put it to sleep, it would sleep, turn off the fans, start pulsing the lights, and then drop power.
    I took it in, and they said it was no problem.
    Then, they decided it was a problem, and wanted to replace the logic board.

    One logic board later, and the problem was not fixed, and now, having been powered off for about 3 weeks, it will not even last long enough to get up to login before dropping the power.

    I have heard rumours that things need cleaning. I would have thought the logic board replacement would have resulted in a lot of cleaning. I have had the memory out and reseated it all, so I am not sure where else I might clean.

    I recently found a thread which indicates that there seems to be a lot of folks with similar problems.

    I have not read thru it all, but observe that the last page has recent activity.

    At some point today, I am going to open her up again and see if there is any place obvious where cleaning might be applied, and at the same time, get it ready to take back in for repairs.

    I'd really like a new Mac Pro, and am waiting, kicking this one along until the new ones come out, thankful that I have some spare iMacs to keep me going.
  5. wafl iron macrumors regular

    Nov 16, 2007
    a coworker of mine used to work for Nvidia QA Engineering and told me that every 8800 was affected by a bad soldering job material that after several cycles of heating/cooling, the solder material on the pcb would get small cracks and cause the cards to fail. This is why you hear a lot of people say that baking the card fixes the problem.

    My 8800gt failed in my machine, luckily i was under apple care at the time, they gave me another 8800gt. Which i promptly replaced with an HD5870.

    I brought the machine in and told them my video card was dead. The guy at the store walked through all the diagnosis steps with me and confirmed it. I even had him try different pci slots so i was certain it wasn't misdiagnosed.
  6. goMac macrumors 603

    Apr 15, 2004
    Honestly, it still sounds like you might have logic board issues if you can't boot OS X.

    When my 8800 went bad I could still boot OS X with a different video card no issue.
  7. nanofrog macrumors G4

    May 6, 2008
    How is the storage system configured in terms of where each OS is located? Same disk or separate disks?

    I ask, as it's possible the OS X installation is damaged (can't load the Kernel).

    The reason I doubt it's the logic board, is a bad board tends to result in no OS will boot at all, which isn't the case here since Windows is loading properly.
  8. goMac macrumors 603

    Apr 15, 2004
    I've seen this sort of behavior when a controller on the board is damaged. The OS tries to keep loading the driver, and eventually crashes.

    That said, you should check your OS X installation. Do a full re-install though. If it is a driver, sometimes the drivers isn't loaded as part of the install disk.
  9. nanofrog macrumors G4

    May 6, 2008
    Statistically speaking, an HDD failure is more common than a blown semiconductor, which is why I asked about the HDD configuration.

    For example, IF both OS's are on the same disk, then it rules out a bad SATA controller. If they're on separate disks, more diagnostics would be involved (full surface scan, try the disk on a different SATA port, ... to determine if it's a bad disk or a bad port).
  10. goMac macrumors 603

    Apr 15, 2004
    OP should most definitely do those things. But given the symptoms, I'm just pointing out that it might be a bit pre-mature to start saying Apple mis-diagnosed. I had exactly this happen with a dead firewire controller once. Everything else booted, including the install disks, except for OS X.
  11. nanofrog macrumors G4

    May 6, 2008

    For me, it had nothing to do with whether the Genius Diagnosis was right/wrong, so I asked a question in order to see if a simple starting point could be determined (KISS approach). ;)
  12. 666sheep macrumors 68040


    Dec 7, 2009
    Sadly it happens quite often when it comes to MPs ;)
  13. Cindori macrumors 68040


    Jan 17, 2008
    this is apple store repair procedure:

    Try boot disk or dvd

    Try PRAM reset

    Try SMC Reset

    Nothing works, replace GPU

    Still doesnt work, replace logic board

    Still doesnt work, replace PSU

    and check some status lights on motherboard in between.

    Really, it's like that. At least the apple store I worked for.
    If you don't have AppleCare, it's usually much cheaper and faster to ask on forums and then order your own parts.
  14. DevinPitcher macrumors regular

    May 23, 2009
    Michigan, USA, Earth
    OP, I just picked up a Mac Pro 1,1 with the same issues you had and the same diagnosis by Apple for $140. $250 for Apple's ATI Radeon HD 5770 Graphics Card Upgrade and I was back in business.
  15. minifridge1138 macrumors 6502a

    Jun 26, 2010
    if the machine boots to windows just fine, then the physical parts are just fine.

    What options do you get when you hold option when it boots?
  16. DevinPitcher macrumors regular

    May 23, 2009
    Michigan, USA, Earth
    Not always. It's a Mac OS X thing I guess.

    OP, boot into safe mode and see if works by holding Shift as it boots. If this works and it shows video, its the card. It will also display 0 MB of vRAM in System Profiler.

    The 7300 GTs had a capacitor problem, and I am almost 99.9999% sure this is the issue.
  17. realchriscasey thread starter macrumors newbie

    Oct 24, 2011
    Hey all, OP here.

    We did a clean install of Lion last night (couldn't find our original Leopard disc; burned the installer from my recent iMac OS upgrade) and the machine is back up and running. We've declared the 8800 officially dead, but with the stock 7300 everything is up and running. I'll be writing a short letter to Apple to let them know my disappointment (had we spent the $700, we would be no better off!). I'm still pretty curious as to why the Leopard install got corrupted (or, failed to boot with the 7300 in place), but all that really matters is that we're back up and running.

    We do still want a new video solution, as the speed on this old card doesn't really cut it for us. I'm looking into swapping in a 6870, as it seems to be a good value proposition and I've heard it isn't much work to get it running under Lion.

    Thanks everyone for the advice and encouragement.

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