MacPro(2,1) Random shutdowns, red light on ram riser

Discussion in 'Mac Pro' started by odwalla, Aug 5, 2016.

  1. odwalla, Aug 5, 2016
    Last edited: Aug 5, 2016

    odwalla macrumors newbie

    Aug 5, 2016
    New York

    First post, but Im a long time lurker. Anyways, I have an issue with my Mac Pro (2,1) with random shutdowns, and a solid red light under "A2". I tried swapping the positions of the sticks and the same red light comes on. I also moved the top riser to the bottom, and same light is lit.

    This issue with the red light occur when I was using old existing ram. Recently, I replaced all ram sticks with OWC and the same solid red light is on under "A2". In system profiler, it says I have 24GB ram and all slots says "OK"

    Is my riser dead or is it another issue?


    Mac Pro (2,1)
    3GHZ Dual Quad Xeon
    El Capitan
    Radeon 7950
    24GB ram

    Any help will be much appreciated, thanks.

    Attached Files:

  2. ActionableMango macrumors G3


    Sep 21, 2010
    I looked this up in the Service Manual, but I have to say that it's very vague and not really helpful because you've already tried everything. :(


    Memory Riser Card Diagnostic LEDs

    Both of the memory riser cards include diagnostic LEDs for each DIMM. Each of the LEDs will light if it detects an issue with the corresponding installed DIMM. These LEDs will also flash briefly when the computer is started up or shut down and when it goes in and out of sleep mode. This is normal behavior.

    • Shutdown and restart the computer.
    • Try reseating the DIMMs.
    • Check memory installation instructions for proper installation order.
    • Swap affected DIMM with known good DIMM.
    • Try moving DIMM to another slot (within the same bank of two) to see if the failure LED follows the DIMM. If so, replace DIMM with known good DIMM.
  3. odwalla thread starter macrumors newbie

    Aug 5, 2016
    New York
    Thanks for trying. I decided to buy a replacement riser off of eBay. Hopefully that will fix the problem. I'll update this thread soon.
  4. odwalla thread starter macrumors newbie

    Aug 5, 2016
    New York
    Fix it, all good now. I bought a replacement riser off eBay for $6. Runs like a champ again.

Share This Page