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27-inch / 27" iMac Random Shut down

160285 Views 498 Replies Latest reply: Jan 8, 2014 3:55 PM by wooffi1 RSS
  • Paul G. Level 1 Level 1 (5 points)
    Currently Being Moderated
    Sep 9, 2012 9:50 AM (in response to Berry with an \"A\")

    In a continuation, here's what happened to me this morning:


    I was up early and wanted to listen to something. To keep the house quiet, I decided to wear some headphone. I took the headphone jack and went to insert it into the hole in the back of the iMac. My attempt was not precise, but going into the hole... the machine suddenly lost power.


    This was the exact same experience as before, but previously it was when the computer was doing an intense process.


    So, my iMac might have something electrical going on... or something that is allowing for it to surge and shutdown. I don't know a lot about electricity, but seems like it is just shorting out.


    That's just an interesting update.

  • oilersrock99 Level 1 Level 1 (0 points)
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    Sep 9, 2012 10:09 AM (in response to Berry with an \"A\")

    I did tell them no, and said that I shouldn't have to buy something external to make the computer work.  That's when they offered to replace the computer straight up for me.  I told them I wanted to try it with the UPS just to be sure it wasn't somthing on our end.  Issues have still persisted - not nearly at anywhere the same frequencies, but still happening.  They ordered it yesterday for me and I should have it in 2-3 weeks.

  • Vince LaMonica Level 1 Level 1 (5 points)
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    Sep 9, 2012 11:06 AM (in response to oilersrock99)

    I've been monitoring this thread for a long time, getting the e.mail updates, and I just wanted to chime in with how my Core i7 27" late 2009 iMac issue was solved. It too would reboot for no reason. It only started when I added 16GB of memory [from OWC, their branded memory]. I live in an area that loses power very often, so I have powerful UPSes hooked up to all electronics [TVs, VCRs, Macs, etc]. Some of the outages last 10 seconds, others for hours, so having things hooked up to battery backup means I don't lose data on computers and I don't always have to reset clocks on other electronic devices


    Anyway, the iMac continues to run 10.6 and I didn't want to upgrade to 10.7 [either in this thread or somewhere else, someone partly solved it by putting Lion on their system].


    For me what solved it was getting Samsung memory from OWC. It's been a year now with that memory and though the iMac has other issues [the hard drive is always writing as it appears an app running in the background leaks memory badly as 5GB are in use after a reboot and an hour of just having the desktop showing and no non-menubar app running], the rebooting stopped completely. Since the hard drive issue seems software related, I'm going to do a clean install of 10.6 and start installing apps slowly but surely to see what is causing the issue [Activity Monitor usually has Safari Web Content as a "Real Mem" hog, but my problem happens even w/o Safari running and nothing in AM shows a lot of memory in use].


    I'm not a big fan of Samsung re: their smartphones, but I will say that using their memory solved my random rebooting issue.

  • Paul G. Level 1 Level 1 (5 points)
    Currently Being Moderated
    Sep 9, 2012 12:19 PM (in response to Berry with an \"A\")

    First off, my situation was never a sudden "reboot" but a sudden death. With that, I suspected RAM was the issue, but now that the headphone jack made the iMac suddenly turn off... it seems like the logic board is the issue.


    There's not a firmware release that will fix this issue and my confidence is a bit blown in the model. It might be the logic board or how electricity and heat move around the entire unit.


    Thanks again for sharing with us, Berry.

  • sbolin Level 1 Level 1 (0 points)
    Currently Being Moderated
    Oct 11, 2012 8:36 AM (in response to Berry with an \"A\")

    Wow, at least I know I'm not alone now with the spontaneously rebooting iMac!

    Same problems as most people here: 16GB ram, iMac restarts randomly, making the computer worthless. I've had it to my Apple authorized reseller (no Apple stores in the country I live) 5 or 6 times now. 3 times ago they _said_ they replaced the power supply, 2 times ago they _said_ they replaced the mainboard, but most times they just wipe the HD and reinstall OSX (ML currently, but doesn't matter which 10.x is installed, problem remains). Interestingly, they DID check the RAM, but said even after they switched it out the machine rebooted, so that is when they changed the mainboard (supposedly - they may just be sick of me complaining about the POS iMac, and just did the usual wipe and re-install).


    I'll try a few days with 8GB RAM, see if that helps. If not...back to the shop.


    Does anyone know how to force Apple to replace the machine? I've had the machine for nearly 3 years, always has troubles, it really is useless for me to use because I often lose data during the restart, so just can't trust to use the machine for anything half way serious. Not sure the process, though - if anyone knows, I'd apprciate it!

  • Leoto Calculating status...
    Currently Being Moderated
    Oct 11, 2012 9:16 AM (in response to Berry with an \"A\")

    I had this exact same problem, and in my case, I found out that there was a short in the PCB on the secondary internal hard drive (Western Digital 1TB Caviar Black).  When I removed/replaced the hard drive, the problem went away.  Different iMacs with the same symptom may have different causes, but in the case of my iMac, a faulty PCB board on the internal hard drive was the cause.

  • sbolin Level 1 Level 1 (0 points)
    Currently Being Moderated
    Oct 11, 2012 9:24 AM (in response to Berry with an \"A\")

    Berry with an "A" - thanks very much! In a way, I'm glad to see that I'm not the only one with this problem. I will point the AASP to this thread, and tell them "See, many many others with this problem - replace my machine, please".


    Pretty bad problem Apple seems to have with the iMac, sort of worried to get a new one. Funny thing was, in 2009 when I got it they had the yellow screen problem, and I was so releaved that my machine didn't have that...little did I know then!

  • noni88 Calculating status...
    Currently Being Moderated
    Oct 11, 2012 9:33 AM (in response to Berry with an \"A\")

    Hello, i just bought my iMac a week ago. It is a 3.4 Ghz Intel Core i7 Memory 16gb. My computer keeps restarting randomly every 5 times an hour! does anyone know what should i do? I am new with mac and i am not pleased with this.

  • Leoto Level 1 Level 1 (0 points)
    Currently Being Moderated
    Oct 11, 2012 9:41 AM (in response to Berry with an \"A\")



    Every now and then (once every few weeks), the computer would instantly shut down out of the blue as though the power plug had been pulled.  Often, it would take a few minutes before I was able to start the computer again. 

    Then, I had one last shutdown after which I became unable to start the computer.  So I opened up the computer and experimented.  When I disconnected my secondary hard drive, I was able to turn the computer back on again.  When I replaced the hard drive with another working one that I happened to have, the computer turned on, and I never got the random shutdown issue anymore.


    As I mentioned before, I don't think similar or identical symptoms necessarily indicate the same cause, but it's just a possibility that might be worthwhile for people to look into if they're having random shutdowns.

  • Gandalf The Grey Level 2 Level 2 (275 points)
    Currently Being Moderated
    Oct 11, 2012 9:43 AM (in response to noni88)

    noni88: I would take it back and wait for the refresh of the new iMacs. I had a June 2011 iMax that went belly up after I put Lion on it, the hard drive failed it kept freezing up and major video issues. Then they replaced the memory and second hard drive then the logic boad, they said it could be repaired and asked me if I wanted a new one. I said no, I wanted a store credit, so I bought my wife a Macbook Pro and I got a loaded Mac Mini and Display, so far so good no issues with those computers. Take it back and wait in my Opinion.


    Berry with an A: I had overheating issues and 2 hard drive failures according to Apple techs, most likely from stopping and restarting the F r i c king thing from the screen freezing.   This all started after Lion, there were slight problems after Snow Lep. last version but got far worse and un-usable after Lion.  I also had the same machine as you did and I miss the speed!

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