Need Mac Pro 2009 - 2012 PSU Pin out

Discussion in 'Mac Pro' started by DrBobF, Jun 8, 2018.

  1. DrBobF, Jun 8, 2018
    Last edited: Jun 8, 2018

    DrBobF macrumors newbie

    Joined:
    Mar 27, 2014
    Location:
    CT
    #1
    Greetings - I'm trouble shooting a 2009 Mac Pro for a no power up problem. The apple custom 980Watt delta power supply pinout is proprietary but the major power rail positions are evident. ( +12/ GND... GND/ +!2 ) The center group of smaller pins have two conductors that when shorted together will power on the PSU, which is, I think, the " power on" signal, normally supplied by the mother board. In the process of load testing the PSU on the bench to check the current spec.
    Does anyone have the full pin out of these center group of conductors?

    Update... I just did a quick load test on the PSU using a 100watt load on each of the 12V rails and forcing the PSU to turn on with the two pins I spoke of.
    PSU seems to be working at this load and being when it is put back into the chassis with only the motherboard, front and rear panels installed with the 5VSB led lighting when the diagnosis button is pressed, it seems the the power on signal to the PSU is not happening. It seems either a connection issue on the mother board or a failure of the power on button/ circuit. A schematic would be handy to troubleshoot this.
     
  2. Macschrauber macrumors 6502

    Macschrauber

    Joined:
    Dec 27, 2015
    Location:
    Germany
  3. DrBobF thread starter macrumors newbie

    Joined:
    Mar 27, 2014
    Location:
    CT
    #3
    Thanks for the information. I just put the PSU on the test bench and shorted the two pins ( must be the "Power On" signal ) out and the PSU turns on. With a fractional load of ~100W on both the A and B outputs, the 12volt rails are stable. Must be a connection, motherboard or front panel issue. Without any of the proprietary ( Not even to developers ) schematics , it is time to get out the DDM and analyzer to see what is not happening. Thanks again. Cheers.
     
  4. Macschrauber macrumors 6502

    Macschrauber

    Joined:
    Dec 27, 2015
    Location:
    Germany
    #4
    A Mac Pro 5.1 board set runs without the front panel. I just put together a backplane board, prozessor board and of course a gpu, a usb boot device and got it booting. No fans, no front panel and no case. I just had to shorten the power on pads on the board.

    Please share what you can sort out, i am too lazy now (without a reason) to put out a PSU for more measurings :)
     

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