Lagoiski

Q: 27 iMac (2012) crashes and requires smc reset to turn on

My late 2012 iMac, i7 16gig RAM 27 inches keeps shutting down. It looks like as if it was unplugged. Happens randomly. Sometimes while playing Diablo 3, surfing facebook or using iphotos or other apps. Seems to not crash if just left on overnight and not been used.

 

In order to turn it on again I have to unplug it from the power line for like 30 seconds, only then it starts.

 

I have the settings set to restart on power failure, but it does not.

 

Happened a few times a few months back. I have installed a surge protector and it worked fine for like a month or two. However last 2 days it has shut down like 10 times...

 

Help would be greatly appreciated. I suspect hardware failure.

iMac (27-inch, Late 2012), iOS 7.1.1

Posted on May 5, 2014 9:44 PM

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Q: 27 iMac (2012) crashes and requires smc reset to turn on

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  • by Glasgood,

    Glasgood Glasgood Sep 7, 2016 1:38 AM in response to NickFromLE
    Level 1 (4 points)
    Sep 7, 2016 1:38 AM in response to NickFromLE

    Thanks for the update Nick,

     

    I can confirm that the PSU that is replaced was also the Delta (Model: ADP-300AF T).

     

    All going well with my iMac since replacing the PSU.

     

    Best

  • by NickFromLE,

    NickFromLE NickFromLE Sep 7, 2016 2:24 AM in response to Glasgood
    Level 1 (22 points)
    Desktops
    Sep 7, 2016 2:24 AM in response to Glasgood

    Thank you too for your update.

    Which PSU you are running now? A new Delta or the liteon?

     

    Cheers,

    Nick

  • by lune-cheung,

    lune-cheung lune-cheung Sep 7, 2016 5:52 PM in response to NickFromLE
    Level 1 (4 points)
    iLife
    Sep 7, 2016 5:52 PM in response to NickFromLE

    Thanks for the great information. 

    I have 128G fusion drive already as a fusion, look like the people using dual connections to boost the speed up to 900Mbs. I may consider that in the future.

     

    I just bought the Samsung 850 Evo 1Tb SSD. I am planning to install this SSD when I swap out the PSU.

     

    Also, The PSU I have bought is a Liteon, and I am still waiting for its arrival.

    The reason I bought the Liteon, because most of the iMac PSU are found as Delta. I suspect Delta has more issues than Delta, I just give it a try.

     

    I will do some stress test once I installed the Liteon PSU. see how does it go?

     

     

    Regards,

     

    Lune

  • by oomoot,

    oomoot oomoot Sep 8, 2016 1:35 AM in response to Glasgood
    Level 1 (4 points)
    Desktops
    Sep 8, 2016 1:35 AM in response to Glasgood

    I have a similar machine. Late 2012 i7 3.4GHz 32GB 680MX. I got my power supply replaced by Apple Store itself in Istanbul around 10 days ago. I never tried to replicate the shutdown problem in safe mode but I even got the shutdowns on the windows 10 partition and another partition that I created for testing purposes.

    Apple Store itself of course couldn't replicate the problem like almost everyone else in here experienced. It's probably down to power supply not being powered on for far too long). But they still replaced the power supply for around 115 US Dollar (340 Turkish Liras)

     

    By the way as far as I'm told it's a 300Watt part. While I was at it I asked them to fit the machine with some other type of power supply made for other,  possibly newer iMacs that utilize a higher wattage part. They refused to do so. Apple policies obviously. I haven't asked about the brands of the outgoing and incoming power supplies. I'd do so if I had read the related posts in here.

     

    Long story short, for the past ten days the machine has always been on, I had played Civ V for like 10 hours at once, max. settings and so far no shutdowns. So, tho Apple Geniuses failed to replicate the problem and tho it seems like a problem Apple itself should acknowledge and pay for, apparently the replacement of the PSU resolved the issue.

  • by Beolion73,

    Beolion73 Beolion73 Sep 14, 2016 4:55 AM in response to lune-cheung
    Level 1 (4 points)
    Sep 14, 2016 4:55 AM in response to lune-cheung

    Hi Lune

     

    Did you have any success with the Liteon PSU, or have you received it?

    Also, after surfing around for this problem on the net, it is sad to see post on so many other forums with users facing similar problems. Apple must have a quite bad taste in their mouth, and maybe they just hope that someday all of us have scrapped our machines :-(

  • by lune-cheung,

    lune-cheung lune-cheung Sep 14, 2016 5:54 AM in response to Beolion73
    Level 1 (4 points)
    iLife
    Sep 14, 2016 5:54 AM in response to Beolion73

    Hi Beolion,

     

    Thanks for your post. Well, I am still waiting for the PSU shipping. As I bought it from China (Aliexpress), it is a bit cheaper but take a bit longer. Therefore, I will let you know how does it go for sure.

     

    Well, I guess it is capacitor issue of the PSU. I believe that one of the manufacture which used some cheap capacitor or resistor. Therefore, it wouldn't last very long.

    Frankly, Apple should fix the problem immediately, Apple should have the quality assurance to ensure their product up to a standard. Although the Apple care can cover the any failure, my PSU has been replaced by apple once. Howeverm It starts to get problem again after 6 months. I am very disappointed about it. Apple is not fixing the root cause, they just replace the bad parts with the same bad parts.

  • by Hank K,

    Hank K Hank K Sep 14, 2016 10:06 AM in response to lune-cheung
    Level 2 (254 points)
    Desktops
    Sep 14, 2016 10:06 AM in response to lune-cheung

    I'm doing the same thing, I ordered mine from China (LAI YI SHENG) and it has been shipped.  Should receive it next week.  The the fun begins, I"ve never open up an iMac before, just Air Books, and iPhones.  

  • by Just it,

    Just it Just it Sep 17, 2016 2:37 PM in response to Lagoiski
    Level 1 (4 points)
    Sep 17, 2016 2:37 PM in response to Lagoiski

    I began to have this problem recently. I tried SMC reset, Apple Hardware test and NVRAM reset for many times. They won't work. The iMac keep shutting down randomly. It is very frustrated when I am writing code. I found this discussion today. Thank you guys for posting your researches and progresses.

     

    My iMac (27", late 2012, 3.4G) had 2 problems now.

    1. The stand broken (Design fault? 27" 2013 iMac stand just gave up!)

    2. Shutting down randomly, and won't start again unless unplugging the power cable.

     

    Apple should definitely call users for these to be repaired, before they causes the users so much confusion.

  • by Hank K,

    Hank K Hank K Sep 17, 2016 2:47 PM in response to Just it
    Level 2 (254 points)
    Desktops
    Sep 17, 2016 2:47 PM in response to Just it

    Have you tried to restart in safe mode?  This is working for us while we await our new power supply.

  • by NickFromLE,

    NickFromLE NickFromLE Sep 17, 2016 2:50 PM in response to Just it
    Level 1 (22 points)
    Desktops
    Sep 17, 2016 2:50 PM in response to Just it

    Hi Just it,

     

    as far as I can report - I started to began shutting down the iMac during night.

    Since this day not a single restart during day.

    Weeks later I replaced the Hard Disk (original 1TB HDD) and now its a killing machine.

    I had this problem and I remember how frustrating that was. I just went off during writing or in the middle of a game.

    It began when I used Safari. I then switched to Firefox and didnt had this shutdowns for 1-2 weeks. I thought I got it but then I shutdown while I was draggin the speaker volume to low. I clicked on the icon and swwwooosh - the mac was off and I wasnt able to bring it back.

    Well - it works for me to shutdown and ! totally unplug the powercable off the wall ! during night.

    Since then I also had it up and running 2 nights because of backups and copy jobs but it was running the next day very well.

    Just try that if you can and see if the things are getting better.

    And let us wait for the guys changeing their PSUs.

     

    Cheers,

    Nick

  • by Just it,

    Just it Just it Sep 17, 2016 7:11 PM in response to Hank K
    Level 1 (4 points)
    Sep 17, 2016 7:11 PM in response to Hank K

    I will try the safe mode, thanks Hank. Also I'll try Nick's method. Thanks.

  • by ngrant,

    ngrant ngrant Sep 18, 2016 4:46 AM in response to Just it
    Level 1 (4 points)
    Desktops
    Sep 18, 2016 4:46 AM in response to Just it

    Hi all,

     

    I solve my shutting down issue.

     

    Replaced the PSU, the old one was a  DELTA, the new one installed now is a Liteon.

     

    I inspected the old one and it showed some signs of heating on the circuit board.

     

    New PSU has been on for more than a week now, iMac has been on all the time, used it for a bit everything, movies, gaming, did a benchmark test to stress it a bit...

     

    all good no shut down.

     

    cheers

     

    Nick

  • by Hank K,

    Hank K Hank K Sep 18, 2016 7:41 AM in response to ngrant
    Level 2 (254 points)
    Desktops
    Sep 18, 2016 7:41 AM in response to ngrant

    Nick,

    Good news.  Thanks.  My new PSU should be here in about a week.  Did you have any issues opening up your iMac?  I've read the iFixit instructions and have bought the tools but are still nervous.

     

     

    Thanks

     

    Hank

  • by Beolion73,

    Beolion73 Beolion73 Sep 19, 2016 4:48 AM in response to ngrant
    Level 1 (4 points)
    Sep 19, 2016 4:48 AM in response to ngrant

    Hi Nick

     

    Thanks for the reply, really hope it solves your issue, others as well. Please let us know regularly how it goes.

    And looking forward to Hank's experience as well.

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