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Thread: Mac Pro not booting

  1. #1
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    Default Mac Pro not booting

    Hi, I'm new to the forum, having tries a few others in the past, but looking through the posts here, it seems like a good place to come to get some help.
    I've got a Mac Pro 3.0ghz, early 2008 that has a boot problem.
    I've checked all of the ram, no problems showing up there, I've reset the SMC in both ways, I've pulled all of the internal drives, booted off those via USB as well as a couple of others using SL and Lion as well but everything comes up with the same result: it freezes soon after the turning wheel comes up, about 15 secs. The only thing that produces a different result is booting off a SL install DVD... that brings up a kernel panic after a couple of minutes.
    I've reset the PRAM as well.
    That leaves me, as far as I can work out, three possible issues:
    1. Bad ram slot, but the POST check is okay and the LEDs indicate all ram is working.
    2. Bad video card - GeForce 8800GT installed.
    3. Bad logic board.

    The last two are virtually impossible to check without swapping them out and that means potential expense if things have to be sent back, restocked etc, presuming that the supplier will accept them back.

    Any suggestions as to other possibilities or other software that can check the hardware would be appreciated.

  2. #2
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    I've also booted the AHT and that tells me everything is working properly... fat lot of good that has ever been!

  3. #3
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    So I have thought on this for a bit... wondering what I would do.... that you haven't. I cannot think of much. Only thing to try is start disconnecting stuff - like hard drives and memory. Generally, when it gets down to the list you have it almost is impossible to do anything without swapping in other parts. Which means an Apple Certified Repair guy. They will be able to swap in a graphics card, memory, motherboard until they locate the problem.

    I don't know any tricks. Might, just maybe, be a small chance that the Kp Log would reference something useful. However I have not very often seen anything that allowed me more than a guess.

    Welcome to the forum. Couple of our folks here are really good at this stuff and will most likely weigh in.

    Rick
    molṑn labe'
    "I am a mortal enemy to arbitrary government and unlimited power. I am naturally very jealous for the rights and liberties of my country, and the least encroachment of those invaluable privileges is apt to make my blood boil."
--Ben Franklin

  4. #4
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    Default Welcome to the Guru's Forums

    You've found the right forum. Now we just need a smarter Moderator. The smart guy just beat me.

    I don't fully trust all the "various test apps" they might say "good" when they really are not.

    Was any of the RAM recently added? Or any other new hardware or software.

    I'm not very familiar with that specific computer but RAM can create many issues. I don't recall how you need to put the RAM in but if you can just use 1 stick or 1 pair try different slots to see if indeed there is a bad slot or even a bad RAM chip. A little time consuming but effective.

    If you can create a "new user" and see if the issues still happen this will eliminate a /users issue or corrupted /users file.

    If you have DiskWarrior and it boots let it run.

    Others will be around hopefully with a better thought. You have hit the obvious or first troubleshooting tips or advice.

  5. #5
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    the POST check for ram isn't a good indicator of whether your ram is actually working. Also bad ram will manifest itself as a problem with everything in your system BUT ram. It will not boot sometimes and boot fine other times only to act like a bad hard drive. Later it acts like the vid card then another time like the optical drive. I had this happen on a Mac Mini a year or so ago. Very hard to diagnose.
    Damien,

  6. #6
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    So, you said you tried some other boot volumes as well......clean install of a retail OS? Just want to be sure there is no chance it could be an OS/software issue.

    Hardware - I would tend to agree: strip it down to minimums; 1 HD, 2 sticks of RAM. Rotate slots and sticks to see if one is bad, and rotate the HD to at least one other slot or external.

    If you running 10.7, you could boot from the recover partition to see what you get......would be nice to boot from the internet recovery option, to remove the entire SATA/USB/Firewire bus. But only the latest hardware is supported, so far.

    Oh, and did you do the extended AHT?

    Next, odds are on the graphics card. Any chance you can come up with a loner?

    Apple repair centers have a very handy AST netboot version of AHT that might shed some light on the diagnosis too.....if you are anywhere near an Apple store or certified Apple Repair Center (reseller).
    "Imagine if every Thursday your shoes exploded if you tied them the usual way. This happens to us all the time with computers, and nobody thinks of complaining." -- Jef Raskin

  7. #7
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    Found this about the 8800 in MacPros:

    The NVIDIA GeForce 8800 GT video card requires Mac OS X v10.5.2 or later and the Leopard Graphics Update 1.0 for proper function. Since some media do not include the appropriate drivers and updates, the computer may start up to a gray screen or kernel panic as a result. Potentially affected media include bundled restoration media and earlier Mac OS X v10.5 retail media.

    To reinstall Mac OS X or start up from the optical drive, follow these steps:

    • Remove the NVIDIA GeForce 8800 GT video card.
    • Install a supported graphics card, such as the NVIDIA GeForce 7300 GT, ATI Radeon X1900XT, or NVIDIA Quadro FX 4500.
    • Start the computer from the Mac OS X media and reinstall the operating system (or perform other tasks as necessary).
    • If Mac OS X has been reinstalled, reboot from the hard drive, update to at least Mac OS X v10.5.2 with Leopard Graphics Update 1.0.
    • Reinstall the NVIDIA GeForce 8800 GT video card.
    "Imagine if every Thursday your shoes exploded if you tied them the usual way. This happens to us all the time with computers, and nobody thinks of complaining." -- Jef Raskin

  8. #8
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    Almost forgot........

    MacPros have diagnostic lights on the LB. Do any light up when it freezes?
    "Imagine if every Thursday your shoes exploded if you tied them the usual way. This happens to us all the time with computers, and nobody thinks of complaining." -- Jef Raskin

  9. #9
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    Good morning peeps!
    Thank you for all of your suggestions.
    I had tried all of them one way or another except for different ram slots on the risers and swapping the graphics card... oh, and the Apple Store s/w.
    On the ram slots, it won't boot at all unless there is ram in the first slot on each riser. I tried putting it into the 2nd slots - they have to be in pairs - and it just sits flashing the boot LED on the power button, which indicates no usable memory.
    The RAM LEDs stay off when it's booted. I have rotated each of the ram sticks in every possible combination through the DIMM 1 slots so unless all 6 sticks (4 original x 1g and 2 x 2gb Crucial) are bad, it isn't RAM that's an issue here.
    I've never liked the AHT as not once in the 25 years I've been using and repairing Macs has it shown up any fault at all.
    No, I didn't bother with the extended RAM test as I have to conclude, for the reasons stated above, that RAM isn't the issue.
    I was wondering if there was any software that could properly test the video card... no, I haven't got a spare I can swap out, but I am working on getting a 'loaner' to test it. Problem is that the guys are 100 miles away and there's going to be some cost involved, about 25, just to do that. I was, therefore, trying to avoid that if possible with a software test first.
    On the other LEDs - which are supposed to help with diagnosing faults the GPU shows up as being present and configured. Not THAT helpful.

    The external drives I have are all retail installs. I've got every flavour of OSX installed on externals, so, again, no possible issues there. So no point in trying to boot off Diskwarrior either.

    Looks like it's going to have to be the 8800GT loaner if I can get one.

  10. #10
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    One other thing that I did was to take out the 8800GT, clean off the pins and try it in the other x16 slot... no difference there either.

  11. #11
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    Quote Originally Posted by unclemac View Post
    Almost forgot........

    MacPros have diagnostic lights on the LB. Do any light up when it freezes?
    Short answer... no.
    At the moment I've taken out the video card, set up one of my drives to auto login and allow full remote management. Never tried this before, but if it will boot without a video card - currently in the freezer - and it allows me access then I'll know for sure that it was the video card that was causing the freeze... sort of ironic that I'm freezing it!

  12. #12
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    Bingo!
    It's booted headless and I'm in. So it has to be the video card!
    Who needs special software when lateral thinking gets the answer

  13. #13
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    I stuck the card in the freezer to see whether it was a heat issue... it wasn't. But what I did find was that by booting off the external drive with it set up for auto login and file sharing on, I was able to see it on the network and access the drives even though it was 'stuck in the boot phase'. It was only visually stuck there.
    Worth bearing in mind for future troubleshooting, rather than just assuming it was stuck half way.

  14. #14
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    Now to come up with something to swap in there to prove the video is the killer....

    Nice work.
    "Imagine if every Thursday your shoes exploded if you tied them the usual way. This happens to us all the time with computers, and nobody thinks of complaining." -- Jef Raskin

  15. #15
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    Ah, not so much of a problem now. I'm 99.99% certain (leaving room for being wrong ) so I've ordered a s/h 8800GT from one of my suppliers, with a six month warranty, to be delivered on Monday morning. Now that virtually all the risk has been taken out it's not a problem.
    Thanks for all your suggestions, I hope that my experience with this will help someone else in the future as well.
    If you've no objections, I might pop in from time to time and see if I can help other people.

  16. #16
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    Oh, and did the freezer make a difference? No. Often works with hard drive failures though.
    When I put the card back in the Mac it still didn't work, but it booted fully and showed up on the network even though the card itself was freezing the screen. Of course, without having a drive set to auto login it would be stuck at the login screen, giving no indication at all whether anything else was functioning or not.

  17. #17
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    Thumbs up Excellent work

    Great job of explaining and troubleshooting. We can always use a helping hand or extra input. Stop by when you can.

  18. #18
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    Thank you. I'll be delighted to do so.

  19. #19
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    Cool
    molṑn labe'
    "I am a mortal enemy to arbitrary government and unlimited power. I am naturally very jealous for the rights and liberties of my country, and the least encroachment of those invaluable privileges is apt to make my blood boil."
--Ben Franklin

  20. #20
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    The more the merrier. I think you will find a surprising lack of BS around here.

    Keep us posted on how this video mystery progresses.
    "Imagine if every Thursday your shoes exploded if you tied them the usual way. This happens to us all the time with computers, and nobody thinks of complaining." -- Jef Raskin

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