Mac Pro 3,1 randomly shutting down, PSU?

Discussion in 'Mac Pro' started by weezerr, Sep 29, 2018.

  1. weezerr macrumors regular

    Joined:
    Nov 7, 2006
    #1
    My beloved tank 2008 octacore has been randomly shutting down on me. It seems to be worse when I try to play a video or gently stress the system. No KP, just instantly goes black and dead.

    I blew out the system with compressed air, reset all the ram. Ram sticks all come up as OK in system info.

    It seems like this could be a failing PSU which seems to be a problem with the 2008? Does that seem right?

    Is this the correct item to buy? The part number is different than what I have found for my machine (661- 4677):

    Would this work fine?

    https://www.ebay.com/itm/Power-Supp...051042?hash=item3d319803a2:g:kVIAAOSw-xVZ6QNl

    Thanks!
     
  2. pl1984 macrumors 68020

    Joined:
    Oct 31, 2017
    #2
    It could also be due to an overheating issue. Before ordering a new power supply I would recommend downloading a copy of iStat Menus and reading the temperatures. Post them to the forum where others can provide feedback as to whether they're a source of concern.
     
  3. tsialex macrumors 601

    tsialex

    Joined:
    Jun 13, 2016
    Location:
    Brazil
    #3
    Check your board for signals of corrosion on the chips/pads of your board, I had to change two corroded logic boards boards with that shutdown problem.
     
  4. ActionableMango macrumors G3

    ActionableMango

    Joined:
    Sep 21, 2010
    #4
    I'm curious, where was the corrosion and was there some sort of unusual factor involved or did it just happen in normal operating environment?
     
  5. tsialex macrumors 601

    tsialex

    Joined:
    Jun 13, 2016
    Location:
    Brazil
    #5
    A little bit everywhere, two Macs originally from cities that have strong sea air corrosion, don't know the correct english term for "maresia".

    I still have both boards, I can take pictures of what is corroded. One you can see it clearly, the other is subtle.
     
  6. crjackson2134 macrumors 601

    crjackson2134

    Joined:
    Mar 6, 2013
    Location:
    Charlotte, NC
    #6
    Sea Air is correct Alex. It’s like a salty humidity.
     
  7. tsialex, Sep 29, 2018
    Last edited: Sep 29, 2018

    tsialex macrumors 601

    tsialex

    Joined:
    Jun 13, 2016
    Location:
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    #7
    This is the less corroded one, if you just look rapidly on the board you think that is almost new. The other is a lot worse.

    Look at the SMD inductor:
    9FCB346F-1589-4399-AA65-E1F72859D0EE.jpeg

    Processor A socket, every capacitor, south bridge heatsink:
    76B38E14-0DCF-4E4B-A85F-763B64970660.jpeg BDF947D0-D7BE-44E1-872D-6C0376633C72.jpeg

    Look how the corrosion went on the pads of the TSOP FWB flash memory that stores the BootROM:
    22326559-3ADF-4DBD-BA36-D8C7BE81A61A.jpeg
     
  8. weezerr thread starter macrumors regular

    Joined:
    Nov 7, 2006
    #8
    Thanks for the reply! the logic board looks pretty flawless to me. Im the original owner, has never been left in super humid environments.

    Reasonable to throw $80 at a PSU and see if it fixes it? Is the one I linked the correct one?

    I will run some temp monitors as well to check for overheating.
     
  9. weezerr thread starter macrumors regular

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    Nov 7, 2006
    #9
    Staying mostly between 40-46 C....
     
  10. pl1984 macrumors 68020

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    Oct 31, 2017
    #10
    That doesn't seem to be cause for concern. Here are the readings for mine, others can chime in as to whether they consider this acceptable or not:

    2008 Mac Pro.png
     
  11. ActionableMango macrumors G3

    ActionableMango

    Joined:
    Sep 21, 2010
    #11
    Shutdown reasons are logged. In some cases even sudden ones like power loss might be logged--I don't know how, maybe the log is appended on the next startup. So it doesn't hurt to check your log even though it's a sudden shutdown.

    Search for "previous shutdown cause" in the log and find an entry that coincides with the time there was an unexplained shutdown. Then check the number against this list. It might provide additional clues.
     
  12. Pressure macrumors 68040

    Pressure

    Joined:
    May 30, 2006
    Location:
    Denmark
    #12
    When it randomly shuts down does the PSU make a "click" noise? And do you manually have to press the power button to shut it "off" before you can turn it on again when it occurs?
     
  13. weezerr thread starter macrumors regular

    Joined:
    Nov 7, 2006
    #13
    No warning or click, it just abruptly shuts off.

    Once I push the power button it starts back up and will last an indeterminate about of time. Sometimes a few days, sometimes it won’t make it past the fans spinning up.
     
  14. Pressure macrumors 68040

    Pressure

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    Location:
    Denmark
    #14
    Try and blow all the dust out of the PSU but do NOT touch the capacitors.
     
  15. weezerr thread starter macrumors regular

    Joined:
    Nov 7, 2006
    #15
    Thats for the reply.

    I just put in a "new" PSU. Thankfully I must not have broken anything as it booted up fine. It was worth the $80 shot in the dark to see if this solves my problem. Fingers crossed!

    The old one certainly is dusty!
     
  16. crjackson2134 macrumors 601

    crjackson2134

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    Location:
    Charlotte, NC
    #16
    Don’t keep us waiting long for results, fingers crossed hoping this cured the problem.
     
  17. weezerr thread starter macrumors regular

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    Nov 7, 2006
    #17
    So far so good! fingers crossed. A decade out of this machine and still relatively snappy.
     
  18. crjackson2134 macrumors 601

    crjackson2134

    Joined:
    Mar 6, 2013
    Location:
    Charlotte, NC

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17 September 29, 2018