What do these diagnostic LEDs mean?

Discussion in 'Mac Pro' started by gadgetfreak98, May 19, 2019.

  1. gadgetfreak98 macrumors regular

    Joined:
    Feb 6, 2009
    #1
    22C243B6-3694-4D68-8BBB-0F819A18471B.jpeg Hi. I have been trying to work methodically through issues with my 4,1->5,1 Mac Pro. All was fine until I had to do a re-clone of my backup drive to my regular startup NVMe drive. Then my Mac wouldn’t start up... no chime, no screen illumination.

    With the help of others and the Apple service manual, I have been trying to trouble shoot. This includes swapping A and B CPUs, going back to my original CPU, only using CPU-A, using only 2 good RAM sticks, cleaning and reinstalling the Northbridge, removing and cleaning the PSU, etc.

    In following the service manual, I got the right diagnostic lights on the backplane when the CPU tray was installed with no CPU or heatsink (e.g., PSU, 5V STBY, EFI_DONE and GPU_OK). However when one CPU was installed I get lights in the attached picture.

    I again removed the CPU and noticed some slightly bent pins, so I straightened those out and tried again. Same... no chime, no screen image. I cannot find advice as to what this series of lights mean, so if you have an idea, please help.

    Note, there are no unusual RAM or CPU LEDs on the CPU tray.

    Thanks for your help!
     
  2. tsialex macrumors 601

    tsialex

    Joined:
    Jun 13, 2016
    Location:
    Brazil
    #2
    EFI_DONE off is a problem with the SPI flash.
    GPU_OK off happens with non Macs EFI GPUs or not working Apple original GPUs

    You should start to test your parts with another Mac, you have more than one problem and it's making the diagnose a lot more difficult. Test your CPU tray with another Mac Pro, test a known working CPU tray with your Mac.
     
  3. gadgetfreak98 thread starter macrumors regular

    Joined:
    Feb 6, 2009
    #3
    Hmm... I like the idea. Just don’t know anyone with a similar working machine....
     
  4. tsialex macrumors 601

    tsialex

    Joined:
    Jun 13, 2016
    Location:
    Brazil
    #4
    If you don't know anyone with a MP4,1 or a MP5,1 to test your parts, see if you find locally a MP4,1 on the cheap. You will diagnose your problematic one and have lots of parts to sell or to keep. It's usually cheaper than buying a PSU+backplane. People usually makes money with this.
     
  5. gadgetfreak98 thread starter macrumors regular

    Joined:
    Feb 6, 2009
    #5
    Intriguing to consider doing. Although I’m getting closer to moving on to an alternate solution. It’s a bit hard to consider putting more and more dollars into a 10 year old machine... Although I would love, love, love to get this to work again...
     

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4 May 19, 2019