Mac Pro huge problem - crazy fans

Discussion in 'Mac Pro' started by NeilPDJ, Nov 6, 2012.

  1. macrumors newbie

    Nov 6, 2012

    Okay, without waffling, I'll try to give as much info as possible here.
    I was doing some hardware updates to my Mac Pro (1,1 - 2006) and so had it running with the door off and the ODD kind of sticking out. I was restarting quite a lot. One time I pressed the power button and it came on but made a popping noise, followed by a gentle burning smell :-( The fans all came on crazy fast and just kept going. The power light is solid white and no other internal LEDs can be seen.

    I've tried removing everything, a bit at a time. Graphics card, ram, hdds, raid card etc. but no change. I then tried testing the voltages on the molex connector for the DVD drive. 12v as expected on one side, but no 5v on the other.

    I therefore assumed power supply was at fault. Got a replacement. Fitted it (fiddly little thing!) and now... Same thing. :( I've gone back to the logic board and unplugged the ODD power lead so I can test it directly on the board and same thing. So... Does this mean I've fried part of my logic board? Popped a capacitor or something? Is there anyway I can find out? Don't really want to take it to the apple store as I get the feeling ill be wasting my time. Plus, it's really heavy to ate on the metro! I also don't want to sink too much more money in it as I've just spent loads on upgrading it and now another £70 on a power supply I may not have needed...

    ANY advice on how to check/if its likely the logic board/if I should replace or repair etc...

    Other info:
    Original Mac Pro (2006/07) model 1,1
    Upgraded CPUs to 2x4 core 3ghz
    20gb ram
    4 x 3tb hdd in raid with hardware controller
    Running ML with chameleon boot (so old hdd on IDE connector for this)
    SSD for os and apps, also on IDE connector
    DVD drive on 'spare' ODD sata connector
    Ati radeon 5770 graphics card

  2. macrumors 68040


    Dec 7, 2009
    Check diagnostic LEDs -> diag button while startup. If it does boot, check temperature sensors reads, get ASD and run full test. You can try with AHT first. If it's broken temp sensor it will detect it.
  3. macrumors 65816


    May 8, 2008
    Hilo, Hawai'i
    No offense, but have you reset the SMC?

    Also, unless I missed it, you don't say whether it actually runs, noise or no noise.

    If it runs, you could see what happens when you install something like the SMC Fan Control program.
  4. macrumors 601


    Jul 3, 2011
    If it operates, I'd find and the the ASD disc image and run that.
  5. thread starter macrumors newbie

    Nov 6, 2012
    You're right, I didn't say. Sorry.
    It doesn't boot, run or give any chime.

    I've checked the diagnostic LEDs and get the orange trickle power, but nothing else. No reds (which I guess is good!) but no green when power on (which I guess is bad)
  6. macrumors 68040


    Dec 7, 2009
    Normally you should get LED 1 yellow and 6,7,8 green when diag button is pressed. Do you have service manual for your MP? If not, get one.

    Triple check PSU cables. Maybe one is striped/damaged and does touch something metal or logic board? Next examine logic board for any burnt components. You'll need to take apart a half of your MP to do that.

    OFC I assume that replacement power supply is fully working.
  7. thread starter macrumors newbie

    Nov 6, 2012
    I just get the one yellow trickle LED. I've tried both graphics cards that I own but no GPU light for either. There is 12v coming in through the booster power for them. One has the fan run instantly on full speed, the other fan doesn't even start up. No main power green light either :(

    I've done SMC resets via both the unplugging method and using the internal button.

    I have a copy of the service manual, thanks. It's pretty handy!

    Checked (multiple times) all cables - and just re-checked again following your suggestion. Removed ram boards, CPU cover, front fan etc to access everything properly. Everything seems fine and no visual problems with components on the motherboard.

    I can only assume the replacement power supply is okay. It is 'new' - still had protective plastic on etc. would be mighty unlucky for them both to have the same fault. Anyone know what voltages I should expect from each connector? I can always check...

    I'm properly stumped. Anything else I can try?


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