5 Replies Latest reply: Dec 18, 2012 11:57 AM by krobin21
krobin21 Level 1 Level 1 (0 points)

Hello,

 

I have a Mac Pro 3.1 (2008), and she just recently went dead, after trying to wake it from sleep mode.

Since then after every boot:

  • the power led is constantly flashing (not the RAM error type),
  • and my 8800GT videocard's fan is spinning like crazy.

The keyboard is not functioning either.

I tried SMC, PRAM reset is obviously out of question, since no video picture is present.

Nothing has been changed in the hardware, before and after the incident.

I also checked the DIagnostic button, it seems normal, upon pushing it, the 2nd lids up in amber color.

Also the RAM leds show no error.

I even tried to the reboot without the video card, but the same symptoms keep persisting.

 

I am not 100% sure whether the Mac Pro could boot without GPU or not. But I am very afraid, it can, and the problem is with the logic board or CPU.

Any suggestions? How to know if the logic board is dead?

 

Thanks!


Mac Pro
  • 1. Re: Mac Pro 3.1 went into coma
    Grant Bennet-Alder Level 8 Level 8 (49,285 points)

    the power led is constantly flashing (not the RAM error type),

     

    There are multiple different patterns to the flashing light, but any flashing light means not enough working RAM to start up.

  • 2. Re: Mac Pro 3.1 went into coma
    krobin21 Level 1 Level 1 (0 points)

    Hi Grant,

     

    there is 12GB of RAM in the machine. They all worked just fine before the coma occured.

    The flashes are short, continous: blinking, like and index signal on a car.

  • 3. Re: Mac Pro 3.1 went into coma
    Grant Bennet-Alder Level 8 Level 8 (49,285 points)

    The ROM-based power on self test is trying to tell you there is not enough WORKING RAM in the machine to start up.

     

    If you need additional debugging help, an appointment at the Genius bar is free -- in warranty or out.

  • 4. Re: Mac Pro 3.1 went into coma
    krobin21 Level 1 Level 1 (0 points)

    As mentioned in the service manual:

     

    • 1 Flash: No RAM is installed or detected. Or, the quick memory test failed. A LED will light up on the memory riser card next to the affected DIMM or empty DIMM slot.
    • 3 Flashes: A RAM bank failed extended memory testing. An LED will light up on the memory riser card corresponding to the affected DIMM.

     

    My Mac deos not produce any of these. There is no pause between the flashes, to distinguish 1 from 3 flashes. Also there are no error signaling red lit leds on the memory risers. I also tried to boot with the original DIMMs, without success.

     

    Any other idea, what these morse codes means?

  • 5. Re: Mac Pro 3.1 went into coma
    krobin21 Level 1 Level 1 (0 points)

    OK my bad. It was a bad memory unit. First I tried with only one memory card, and the precious rose again!

    Now with a little swapping, I narrowed the problem to one little bugger.

     

    Thanks again Grant!