Catro91

Q: Mac Pro 3.1 black screen, loud fans

Hello community,

 

I have a Mac Pro 3.1, 2008 dual 2.8ghz computer. I bought it cheaply as the original owner claimed it had a problem where it would randomly sleep, and a hard reset was neccesary in order to restart the computer. On turning on the computer myself I soon saw what he meant, all of a sudden, quite randomly the screen would drop out entirely and about 8 seconds later the fans go on full whack. This could happen before the computer boots, or could happen 15 minutes later. Sometimes it would happen more often when say I watched a youtube clip on full size in 720/1080p. This shut down can only be stopped by hard resetting the unit.

 

Originally i thought it might of been the graphics card (Nvidia 8800 GT) which upon researching had found out there have been issues with this graphics card for other people in the past, however they speak of glitchy graphics, over-heating and 'baking' the card. I tested the temps on the gfx card and they were not abnormally high at all. Infact on monitoring all the temperatures when the computer was on i noticed no abnormality with any temps apart from maybe the north bridge which was max 62 C when idling. But my macbook pro hits 75 C on the CPU when using intensive software (logic pro etc). I also tested the gfx card in both available pcie slots aswell as cleaning out excess dust from the gfx card using compressed air.

 

The computer has a WD velociraptor 128gb 10k rpm HDD installed. I tested the computer with a 128gb SSD which i know worked. I managed to install snow leopard from a DVD onto it before a crash and the computer worked for maybe 20-25 mins then it blacked out again. Not the hard drive then. Tested all the ram (6gb), moved them around etc, no red dimm lights on either board. Not the ram.

 

The only main components left really are the power supply and the logic board. I have no red leds on the logic board lighting up, so no obvious failures. And when the computer is on it works a treat.

 

Does this sound like the PSU is dying/dead? I thought this could be an easy software fix, but am now chasing the hardware train....

 

Any help would be greatly appreciated and thanks in advance!

 

Cheers!

 

Catro

Mac Pro, Mac OS X (10.6.8)

Posted on Jun 2, 2014 3:00 PM

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Q: Mac Pro 3.1 black screen, loud fans

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  • by wallacepost,

    wallacepost wallacepost Jun 26, 2016 1:15 AM in response to lllaass
    Level 1 (4 points)
    Desktops
    Jun 26, 2016 1:15 AM in response to lllaass

    This is what i exactly bought from them 2 years ago, 4gb x8pcs = 32GB.

     

     

    Screen Shot 2016-06-26 at 6.13.19 PM.png

  • by wallacepost,

    wallacepost wallacepost Jun 26, 2016 1:42 AM in response to lllaass
    Level 1 (4 points)
    Desktops
    Jun 26, 2016 1:42 AM in response to lllaass

    I bought this 2 yrs ago from the by seller.

     

     

    picture attachedScreen Shot 2016-06-26 at 6.13.19 PM.png

  • by lllaass,

    lllaass lllaass Jun 26, 2016 1:52 AM in response to wallacepost
    Level 10 (188,781 points)
    Desktops
    Jun 26, 2016 1:52 AM in response to wallacepost

    It looks like they are Micron brand. See if they have a lifetime warranty.

     

    Also they do not says they are Error Correcting Code (ECC) memory. The Mac Pros came with ECC memory but can use non ECC memory but you can't mix ECC and non-ECC memory. Were you mixing them?

  • by wallacepost,

    wallacepost wallacepost Jun 26, 2016 2:13 AM in response to lllaass
    Level 1 (4 points)
    Desktops
    Jun 26, 2016 2:13 AM in response to lllaass

    Hi lllaass,

    I didn't mix them, because i was just testing pair by pair.

     

    Im trying to contact the seller, it is going to cost lot money send it back to the seller from Aus to USA.

    I doubt if they think it is memory error, as i can't proof the error by software...

  • by Grant Bennet-Alder,

    Grant Bennet-Alder Grant Bennet-Alder Jun 26, 2016 7:54 AM in response to wallacepost
    Level 9 (60,909 points)
    Desktops
    Jun 26, 2016 7:54 AM in response to wallacepost

    Power light blinking says, "not enough WORKING RAM to start up".

  • by wallacepost,

    wallacepost wallacepost Jun 27, 2016 6:58 AM in response to Grant Bennet-Alder
    Level 1 (4 points)
    Desktops
    Jun 27, 2016 6:58 AM in response to Grant Bennet-Alder

    Hi lllaass & Grant,

    Thanks for both your helping , i m very appreciated!

    It seems all rams failed from eBay. because since i put the old ram back to the mp 4x 1gb, the was no more black screen in last 48 hrs. Im gonna send those rams back to USA seller.

    The only thing has caught my attention, the mp is not waking up if i put it into sleeping for several hours.  i reckon this is going to be another post...

     

    Again, thank you both!

  • by wallacepost,

    wallacepost wallacepost Jul 2, 2016 5:13 AM in response to lllaass
    Level 1 (4 points)
    Desktops
    Jul 2, 2016 5:13 AM in response to lllaass

    the black screen came back yesterday... i wonder if the GPU..

  • by wallacepost,

    wallacepost wallacepost Jul 28, 2016 6:32 AM in response to lllaass
    Level 1 (4 points)
    Desktops
    Jul 28, 2016 6:32 AM in response to lllaass

    I received the new replacement of the Ram's. The black screen issue hasn't been improved. so not the bad Ram caused it

    -------

    2 days ago, i got my new mp 2012, I swapped the HD 7950 to ATI 5770 . the mp 2008 seems back to normal, expected once when i was plugging the USB keyboard in, the screen went black.

    I wonder if the HD7950 was drawing too much power from Pcle slot or perhaps the PSU issue/ riser tray? i had the HD7950 on my mp 2008 for last 3 years, it was fine...

     

    " HD 7950" It is running fine on the mp 2012, so the card has no problem at all. at least we narrow down the problem. the only thing i haven't tried which is to test out the riser cards & PSU...

     

    Can anyone help, please?

  • by wallacepost,

    wallacepost wallacepost Jul 29, 2016 8:46 PM in response to wallacepost
    Level 1 (4 points)
    Desktops
    Jul 29, 2016 8:46 PM in response to wallacepost

    AHT test result, but the ode ram a new replacement and tested from the ram seller

    image.png

  • by lllaass,

    lllaass lllaass Jul 30, 2016 12:54 AM in response to wallacepost
    Level 10 (188,781 points)
    Desktops
    Jul 30, 2016 12:54 AM in response to wallacepost

    For the memory problem, try removing pairs of memory to find the bad memory module pair. Use different slots since maybe yo have a slot problem instead.

     

    For the graphics card, did yo connect the AUX power from the logic board to the card? I do not remember if the card has one or two connections. If two connections both have to be used.

    Are yo using the same cable(s) as on the 2012 MP?

    If only one card connection try both AUC connections on the logic board.

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