Results 1 to 15 of 15

Thread: Nasty mid-2011 27" iMac reboots on shutdown

  1. #1
    Join Date
    Feb 2012
    Posts
    265

    Default Nasty mid-2011 27" iMac reboots on shutdown

    Every time I shut it down, 10 seconds later it boots up again. The console tells me that the shutdown command is telling it to reboot!
    It doesn't matter whether I'm booting off an internal drive or an external drive with the internal plugged in or unplugged.
    I doesn't matter if I'm booting in Yosemite or Lion, the same thing occurs.
    I've tried every means of shutting down, including command line -h and it still does it.
    Ive done SMC and PRAM resets, swapped out the memory, clean installed Yosemite and Lion, no change anywhere.

    Any suggestions?
    The opposite of what you automatically assume to be the truth is the answer you're looking for!

  2. #2
    Join Date
    Aug 2001
    Location
    Grangeville, ID USA
    Posts
    9,148

    Default

    Disconnected all USB devices during shutdown, left them disconnected?
    molṑn labe'
    "I am a mortal enemy to arbitrary government and unlimited power. I am naturally very jealous for the rights and liberties of my country, and the least encroachment of those invaluable privileges is apt to make my blood boil."
--Ben Franklin

  3. #3
    Join Date
    Feb 2012
    Posts
    265

    Default

    The only thing remaining connected on the external boot drive shutdown was the drive itself but unplugging that the moment the power was cut still resulted in a reboot.
    The only way that I can stop it rebooting is to switch off at the wall when it completes shutdown.
    What I'm seeing in the console right now is a string of kernel: Firewire GUID ffffffffeffffff is invalid!
    The opposite of what you automatically assume to be the truth is the answer you're looking for!

  4. #4
    Join Date
    Feb 2012
    Posts
    265

    Default

    Reinstalling Yosemite, or Lion, on the internal drive without anything plugged in at all makes no difference. The ONLY thing that has changed right now is that the kernel warning noted above has taken over from the Shutdown initiated reboot... that's no longer there. Most weird.
    The opposite of what you automatically assume to be the truth is the answer you're looking for!

  5. #5
    Join Date
    Aug 2001
    Location
    Grangeville, ID USA
    Posts
    9,148

    Default

    Something screwed up on the firmware....
    molṑn labe'
    "I am a mortal enemy to arbitrary government and unlimited power. I am naturally very jealous for the rights and liberties of my country, and the least encroachment of those invaluable privileges is apt to make my blood boil."
--Ben Franklin

  6. #6
    Join Date
    Jan 2006
    Location
    Boise
    Posts
    991

    Default

    Awesome Rick!

  7. #7
    Join Date
    Feb 2012
    Posts
    265

    Default

    Not sure that helps me a great deal... I've done the latest EFI update - the only one that's possible to download for this Mac and no difference there either.
    I'm being forced into concluding that there's a logic board fault. It also decides to restart itself if left idle for half an hour or so.
    The opposite of what you automatically assume to be the truth is the answer you're looking for!

  8. #8
    Join Date
    Aug 2001
    Location
    Grangeville, ID USA
    Posts
    9,148

    Default

    I don't have a clue how you'd fix a firmware problem. A firmware issue or a hardware issue is all the same, have to swap out the board to get it.

    Rick
    molṑn labe'
    "I am a mortal enemy to arbitrary government and unlimited power. I am naturally very jealous for the rights and liberties of my country, and the least encroachment of those invaluable privileges is apt to make my blood boil."
--Ben Franklin

  9. #9
    Join Date
    Feb 2001
    Location
    on the landline, Mr. Smith
    Posts
    7,791

    Default

    Yikes.

    With everything reset.....a new OS install....what else?

    One RAM stick at time? Unplug SATA buses, one at a time, and boot external? Not much left.

    Does it behave the same from Safe Mode? How about single user?
    "Imagine if every Thursday your shoes exploded if you tied them the usual way. This happens to us all the time with computers, and nobody thinks of complaining." -- Jef Raskin

  10. #10
    Join Date
    Feb 2012
    Posts
    265

    Default

    Took out both sticks of ram, put in one of mine. Done.
    Safe mode. Done.
    SU mode. Done.
    Verbose mode. Done
    SATA disconnected. Done.

    Everything done that I can think of and more that I'd never considered or had to do before. Still the same issue.
    Conclusion? Bad logic board.
    Suggestion? Immediately after shutdown, switch off at the wall - we can do that in the UK. It doesn't restart then. Otherwise throw a load of money at a new logic board and hope that's the only issue.

    Interestingly, in spite of the kernel/firewire warning, it booted normally off my firewire drive... and then restarted when I shut it down! I give up!!!
    And I don't do that very often.
    The opposite of what you automatically assume to be the truth is the answer you're looking for!

  11. #11
    Join Date
    Feb 2001
    Location
    on the landline, Mr. Smith
    Posts
    7,791

    Default

    Power strip with a switch?
    "Imagine if every Thursday your shoes exploded if you tied them the usual way. This happens to us all the time with computers, and nobody thinks of complaining." -- Jef Raskin

  12. #12
    Join Date
    Jun 2002
    Location
    Lawrenceville, New Jersey, USA
    Posts
    220

  13. #13
    Join Date
    Aug 2001
    Location
    Grangeville, ID USA
    Posts
    9,148

    Default

    That's pretty cool. Didn't know those existed.
    molṑn labe'
    "I am a mortal enemy to arbitrary government and unlimited power. I am naturally very jealous for the rights and liberties of my country, and the least encroachment of those invaluable privileges is apt to make my blood boil."
--Ben Franklin

  14. #14
    Join Date
    Feb 2001
    Location
    on the landline, Mr. Smith
    Posts
    7,791

    Default

    You sir, get a blue star.

    Knew it was possible, but thought one had to have the original firmware....was unaware they were available. Nice!
    "Imagine if every Thursday your shoes exploded if you tied them the usual way. This happens to us all the time with computers, and nobody thinks of complaining." -- Jef Raskin

  15. #15
    Join Date
    Mar 2001
    Location
    Virginia... where one Democrat CAN make a difference
    Posts
    2,929

    Default


    Before you go there... I have an idea. it's old voodoo but worth a shot. Mr Greentree gave me this

    Quote Originally Posted by Greentree
    Remove ram. remove power cord. remove battery. Reset cuda/ PMU, push pwr button. insert pwr cord and boot yes without ram if you get a beep then ur back in business. put ram back in. if not as above but press pwr and cuda together. have had this issue with a good few G4's and this always fixes them. if not. then leave overnight with pwr out. battery and ram out and when you come in in the morning press pwr button on front one last time. then pwr up. Goodluck
    Also this could be a bad motherboard battery they cause all sorts of weird issues.
    Damien,

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •