Dual G5 random shutdowns - PMU?

Discussion in 'PowerPC Macs' started by decksnap, Sep 8, 2006.

  1. macrumors 68040


    Apr 11, 2003
    My system has randomly shut down twice now in the last two days. Dual G5 2.3. I checked the console log, which I know very little about, and it said this:

    localhost kernel[0]: ApplePMU::pMU forced shutdown, cause = -122

    Two questions-

    what's the -122 code mean?

    Do you think resetting the PMU would be the solution to this?
  2. thread starter macrumors 68040


    Apr 11, 2003
    Interestingly, the Apple support pages say my system doesn't even have a PMU, but rather an 'SMU'. So why does the console say PMU???

  3. Guest


    May 26, 2004
    Randy's House
    It is normally a small button under the RAM.

    Also try holding CMD-OPT-O-F on startup and then enter reset-all.
  4. macrumors regular

    Mar 8, 2005
    Hanover PA
    Can you give us an update? Did it solve your problem?
  5. thread starter macrumors 68040


    Apr 11, 2003
    Nobody's answered either of my questions so I haven't acted on it. Thanks for the bump though. Very curious to see a list of the error codes. And why console says PMU when I have an SMU.
  6. macrumors newbie

    Oct 2, 2006
    San Francisco, CA
    G5 dual random shutdown

    I had the same problem, but only after updating to OS 10.4.7 from 10.4.5. After several days of extreme frustration, I reinstalled 10.4.5, and all was well.

    Today I just tried updating to 10.4.8. Same problem is now happening:

    localhost kernel[0]: ApplePMU::pMU forced shutdown, cause = -122

    Anybody know what could be going on?
  7. thread starter macrumors 68040


    Apr 11, 2003
    So you've isolated it to software?

    I''m on 10.4.7.

    I've tried resetting the SMU, resetting the pram. Got a new surge protector.

    I've basically been able to reproduce the problem by opening two or three quicktimes at the same time, and/or adding iTunes into the mix. I will see what happens when I upgrade to 10.8.
  8. macrumors newbie

    May 31, 2006

    check the console crash log and look for a error report (-122)

    google that along with "random shutdowns G5"

    the problem is like an epidemic.

    extrodinarily random and from what ive learned, no way to ensure a solid fix.

    my g5 is getting the CPU and power supply replaced, first time after 6months... i havent even finished payments on this (2nd gen dual 2.5) G5, and im just a kid who relys on his computer to make art and music on... i cant afford a new one, and now at worst ill be using a defective machine that has a trip to the emegency room every so often at MY expense. and if not that, ill just use it constantly fearing it'll crash on me. im sad about this.

    but i dont have faith its going to be reliable still...

    theres still the logic board, cooling system, video card...

    i noticed this problem is occuring with the macbook pros too.
  9. macrumors newbie

    May 31, 2006

    that link explained the error code, -or what could be said for it at least.
  10. thread starter macrumors 68040


    Apr 11, 2003
  11. macrumors newbie

    Nov 22, 2010
    ApplePMU::pMU forced shutdown, cause = -122 A solution?

    Guys, I've had ApplePMU::pMU forced shutdown, cause = -122 for years. I tried everything without success so far...
    Today, out of the blue, I seem to have found a solution. The culprit seems to be a faulty clock and Pram battery. Even if the internal clock functions regularly, a lower voltage from the battery could cause all kinds of strange behaviour. I replaced the battery today and was able to run 5 youtube videos simultaneously, with processor speed to automatic and did not have any shutdown. This morning playing a single video would cause the shutdown...

    So, I don't want to raise false hopes but replacing he battery is definitely worth a try!


    Mr Michele From Italy.
  12. macrumors newbie

    Dec 10, 2010
    So it has been several weeks since you came across this possible fix - have you had the shutdown since replacing the battery?
  13. macrumors newbie

    Nov 22, 2010
    Yes. I am afraid I had a few shutdown but definitely less. I also introduced another change: Instead of disconnecting the main power source from the computer with a switch, I always keep the mac connected, even when It's switched off.

    This seems to "do some good".

    Im am sorry I can't say the solution is 100% effective thought.

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