Having to reset iMac PMU / SMC all the time

Discussion in 'iMac' started by LEESDC, Jul 26, 2017.

  1. LEESDC macrumors newbie

    LEESDC

    Joined:
    Jul 26, 2017
    Location:
    Berlin
    #1
    Hello everybody.

    I hope I can find some helpful feedback here. Likewise, that maybe the thread can help others too.

    Situation:

    I've developed a problem from one day to the next. My iMac will by all accounts turn itself off upon falling to sleep/putting disks to sleep. The computer is silent. The screen black. The mouse and keyboard are unresponsive. There is no response to pushing the power button.

    I've tried a number of things, that I will details below but the only solution appears seems to be to constantly having to reset the PMU (remove power cable at both ends, wait, reconnect and power up).

    The iMac has performed outstandingly up until this point.

    Troubleshooting attempts:

    I've tried various things I found to similar problems I read about online. Resetting the Pram/NVRAM, removing any external devices. Unchecking 'Put hard disks to sleep when possible' in energy saver. But none of these have helped.

    I noticed in system report that AutoPowerOff Enabled is on. I of course can't say if that was on before, or if it should be on?

    Running a diagnostic test reported: No issues found.
    I have to point out that upon clicking 'restart' after finishing this test, the iMac just switched itself off instead.

    Product details:

    iMac: 27inch. Made late 2013.
    Processor: 3.4Ghz i5 Intel Core i5
    Memory: 16 GB 1600 MHz DDR3
    Startup disk: Macintosh HD
    Graphics: NVIDIA GeForce GTX 775M 2048 MB
    Operating System: macOS, version: 10.12.6
    Storage capacity: 3.12TB Fusion Drive

    I would be very grateful to hear if there are any other reports like this. And of course if someone knows of a solution.

    The computer isn't really that old and has been kept in very good condition. I would hope that this is not a sign of a hardware problem? If it is, is there a way I can find out before having to take it to a store?

    Many thanks in advance to you all.
     
  2. cynics macrumors G4

    Joined:
    Jan 8, 2012
  3. Taz Mangus macrumors 68040

    Taz Mangus

    Joined:
    Mar 10, 2011
    #3
    Can you force the issue to happen by manually putting the computer to sleep (menubar->Sleep)?

    Try booting into safe mode and see if the issue can be reproduced. If it can't then you have something installed that is causing the issue.
     
  4. ZipZap macrumors 601

    Joined:
    Dec 14, 2007
    #4
    It it fails when it sleeps, I would also consider that the Hard Drive may be starting to fail.
     
  5. jlseattle macrumors 6502

    jlseattle

    Joined:
    Jan 9, 2007
    Location:
    Seattle WA
    #5
    My vote is hard drive failure too. It starts acting twitchy at the beginning of a major failure. I would back-up everything just in case.
     
  6. cynics macrumors G4

    Joined:
    Jan 8, 2012
    #6
    Replying to my own post.

    Auto power off should be disabled (OP mentions its enabled) the above terminal command will disable it "sudo pmset -a autopoweroff 0" minus quotes.

    Using "peset -g | grep autopoweroff" in terminal should display "0" for an iMac (unless you want it to power off automatically of course).

    Screen Shot 2017-07-28 at 5.13.03 PM.png
     
  7. LEESDC thread starter macrumors newbie

    LEESDC

    Joined:
    Jul 26, 2017
    Location:
    Berlin
    #7
    Many thanks for this. I am trying this now and will see what effect it has this evening.
     
  8. SaSaSushi macrumors 68040

    SaSaSushi

    Joined:
    Aug 8, 2007
    Location:
    Takamatsu, Japan
    #8
    Technically speaking, AutoPowerOff enabled does not shut the machine down but rather puts it into a deeper hibernation mode called "safe sleep" after 4 hours of sleep connected to AC.

    It is an implementation of European energy standards. You can find information about it on this page at the Apple site.

    It takes a few extra seconds to resume but is a power-saving feature and is only supported on Late 2012 or newer iMacs and is enabled by default.

    I prefer the deeper sleep mode and don't mind the extra few seconds to resume so I leave it enabled.
     
  9. LEESDC thread starter macrumors newbie

    LEESDC

    Joined:
    Jul 26, 2017
    Location:
    Berlin
    #9


    Hi, I can confirm that AutoPowerOff being off has no effect and the issue persists.
    --- Post Merged, Jul 29, 2017 ---

    I can force the issue to happen by manually putting the computer to sleep. Once the disks spin down, it is impossible to wake the computer via keyboard/mouse/pressing the power button.
     
  10. cynics macrumors G4

    Joined:
    Jan 8, 2012
    #10
    Well that is unfortunate.

    When your iMac shuts off/becomes unresponsive is the internal LED still on or is it off?

    You can find it slightly to the left (looking at the screen) of the Apple logo looking up into the intake vents. Find it first, then check it when its unresponsive.

    FullSizeRender.jpg
     
  11. LEESDC thread starter macrumors newbie

    LEESDC

    Joined:
    Jul 26, 2017
    Location:
    Berlin
    #11

    Hi Cynics. I can confirm that when the disks spin down the LED is no longer visible..
     
  12. LEESDC thread starter macrumors newbie

    LEESDC

    Joined:
    Jul 26, 2017
    Location:
    Berlin
    #12
    Hi, what does it mean when the internal LED is no longer on when it shuts down?
    Thank you in advance!
     
  13. Fishrrman macrumors G4

    Joined:
    Feb 20, 2009
    #13
    OP:

    See that you're still here (and perhaps still having the problem).

    I have a suggestion for you. It IS NOT "a solution", but a "workaround" that might help.

    Set up your energy saver panel like this:
    Computer sleep - NEVER
    Display sleep - whatever you wish
    UNCHECK "put hard disks to sleep when possible" (you DON'T want the HDD to stop spinning)
    UNCHECK "enable power nap" (if it's there)

    The idea is to keep the computer from sleeping, and to keep the hard drive from spinning down.
    You DO want the display to darken, however.

    I suggest you set up and run this way for 1 week.
    Again, NO it does not "solve" the problem.
    It works around it.
    If the computer/drive never sleep, then they can't "fail to wake up again".
     
  14. LEESDC thread starter macrumors newbie

    LEESDC

    Joined:
    Jul 26, 2017
    Location:
    Berlin
    #14



    Many thanks for this. I am doing this at the moment.

    Do you know what it means when after it shuts off, no diagnostics LEDs are showing? (even though it is still has a mains supply).
     
  15. SaSaSushi macrumors 68040

    SaSaSushi

    Joined:
    Aug 8, 2007
    Location:
    Takamatsu, Japan
    #15
    It usually means a failing power supply. LED #1 should remain on at all times when the iMac is connected to a power source, even when shut down or in sleep. It should only turn off when it is disconnected from the AC power source.
     

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