Mac Pro 2008 3.1 insomnia and other problems

Discussion in 'Mac Pro' started by treo360, Oct 28, 2014.

  1. treo360 macrumors member

    Jun 22, 2009
    I will cut to the quick:
    Mac Pro 3.1
    OS 10.10
    6gb ram
    ati (Flashed with boot screen) 4870 512mb
    4tb of hd space interspersed between all the bays

    Now when I try to put it to sleep I hear what sounds like the PSU clicking and then the computer shuts down and then restarts (I have failure on power to auto restart on). Then, it will either restart and boot just find, or it goes through the process, I see the progress bar and will promptly "Click" and shut down. Then it goes through the whole process and boot or rinse and repeat.*Too often I have to pull the power cord off and let it sit before trying again.

    It does this too on cold boots sometimes. Whether in OS X or Win 8 it doesn't matter. Sometimes it's fully loaded and the "click" off she goes.

    I've looked at the diagnostic lights, everything checks fine, GPU and PSU green, no lights on the riser boards. I look when it boots and then shuts off with that click noise and I see over temp a and b light up briefly.

    I've disassembled the heat sinks and reapplied the thermal grease, heck I've even swapped the sinks to make sure the sensors are reading the cpu's correctly; 25c and 28c for both at the sinks regardless of which sink is on what, with an ambient air temp of 22c.

    Yes I've reset the SMC and PRAM all to no avail, and yes it's up to date on the FW. This has been going on for two years now.

    I'm leaning towards a new PSU, I think there might have even been a thread on a problem similar to this, but before I plunk some money on a PSU I'd like to know what you are thinking.

    I love my mac when it's working :)
  2. treo360 thread starter macrumors member

    Jun 22, 2009
    Today same problem but from a cold boot. I have to disconnect the power cable for 15 min just to get it to boot.


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