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 lune-cheung,

    lune-cheung lune-cheung Oct 4, 2016 3:14 AM in response to Beolion73
    Level 1 (4 points)
    iLife
    Oct 4, 2016 3:14 AM in response to Beolion73

    Just a report update. I have replaced the Liteon PSU for 2 weeks. I haven't experience any problem.

    I do agree Hank K, the screen is a bit brighter with the Liteon PSU.

  • by oomoot,

    oomoot oomoot Oct 4, 2016 4:14 AM in response to lune-cheung
    Level 1 (4 points)
    Desktops
    Oct 4, 2016 4:14 AM in response to lune-cheung

    I got mine replaced approx. 2 months ago by Apple itself. I'm not sure what PSU they put in but it's all safe and sound without any shutdowns

  • by lune-cheung,

    lune-cheung lune-cheung Oct 4, 2016 4:18 AM in response to oomoot
    Level 1 (4 points)
    iLife
    Oct 4, 2016 4:18 AM in response to oomoot

    Hi Omoot,

     

    I had my PSU replaced by Apple before. They actually wouldn't replace different parts for you, I have asked one of the Apple Technician who replaced my PSU before.

    They will still put the original Delta one in your PSU.

    My PSU replaced by apple about 9 months ago( January 2016) , which was still under warranty. However, the shutdown issue happened again around (June).

  • by oomoot,

    oomoot oomoot Oct 4, 2016 5:06 AM in response to lune-cheung
    Level 1 (4 points)
    Desktops
    Oct 4, 2016 5:06 AM in response to lune-cheung

    I thought they have both Delta and LiteOn ones in their inventory and it's just pure luck what you'll get. Am I wrong?  If it happens again I'll try to get a LiteOn one

  • by mike_west_australia,

    mike_west_australia mike_west_australia Oct 7, 2016 10:25 PM in response to mike_west_australia
    Level 1 (4 points)
    Oct 7, 2016 10:25 PM in response to mike_west_australia

    I've been using iStat to see if I can discern any temperature or current anomalies just prior to a shutdown from the graphs it produces.  I can't see any and I'm beginning to think that those that are saying it is a fault in the power supply units might be right. 

     

    I can't afford a new computer at the moment so I will probably have to punt on getting the PSU replaced by the local Apple Shop in the hope that will fix the problem.  If it doesn't fix it I will seriously think about going to the dark side.

  • by inge.a_son,

    inge.a_son inge.a_son Oct 8, 2016 2:20 AM in response to mike_west_australia
    Level 1 (4 points)
    Desktops
    Oct 8, 2016 2:20 AM in response to mike_west_australia

    At my home my late 2012,  27" iMac used to shut down every day, sometimes several times. I used to unplug the computer overnight to stop this behaviour.... then I had Apple service center testing my computer... At first they found nothing wrong with my iMac! I insisted that they should continue (I was away on vacation for two weeks) At the 12th day of constant stress testing, the computer finally shut down completely. Apple service center replaced the power supply (PSU) and that is the end of the story.... I hope... Cost me about 250 Euros to fix this because my apple care plan just ended.    The iMac has worked perfectly since... 70 days of very intensive use and so far so good!

    My specs:

    • iMac (27 inches, late 2012)
    • 3,4 GHz Intel Core i7
    • 8 Go 1600 MHz DDR3
    • NVIDIA GeForce GTX 680MX 2048 Mo
  • by Just it,

    Just it Just it Oct 10, 2016 5:20 PM in response to Just it
    Level 1 (4 points)
    Oct 10, 2016 5:20 PM in response to Just it

    Hi Nick,

    Shutting down iMac overnight and also unplugging the power cable work for me.

    Before I just shutdown iMac overnight without unplugging the power won't work.

    Thanks Nick.

  • by NickFromLE,

    NickFromLE NickFromLE Oct 10, 2016 11:31 PM in response to Just it
    Level 1 (22 points)
    Desktops
    Oct 10, 2016 11:31 PM in response to Just it

    Hi Just It,

    nice to hear.

    I now use a wireless remote control to unplug to cable. Its a bit easier every night

    Good thing is that still there is no single shutdown since I started it. Even if it runs during the whole day.

    I really think they have a problem with 24h powersupply. The smc may needs to "rest" sometime :-)

     

    Cheers,

    Nick

  • by Hank K,

    Hank K Hank K Oct 11, 2016 12:59 AM in response to Lagoiski
    Level 2 (254 points)
    Desktops
    Oct 11, 2016 12:59 AM in response to Lagoiski

    Well, I did it!  Changed out the Delta PS for a Liteon, now we'll see if the fix works!

     

    For one thing, the screen is much brighter.  I might have to adjust

  • by Hank K,

    Hank K Hank K Oct 11, 2016 1:01 AM in response to Hank K
    Level 2 (254 points)
    Desktops
    Oct 11, 2016 1:01 AM in response to Hank K

    Since the new Liteon PSU was installed, the baby has been perfect.   I'm convinced that the problem is in the or Delta PSU. 

     

    Apple needs to be honest and recall these Macs. 

     

     

    Hank

  • by mike_west_australia,

    mike_west_australia mike_west_australia Oct 11, 2016 1:17 AM in response to Hank K
    Level 1 (4 points)
    Oct 11, 2016 1:17 AM in response to Hank K

    Apple needs to be honest and recall these Macs.

     

    I expected better of Apple than this.

     

    They appear to be hoping that the affected users like us will just give up.

  • by zdz80,

    zdz80 zdz80 Oct 14, 2016 4:51 PM in response to mike_west_australia
    Level 1 (4 points)
    Oct 14, 2016 4:51 PM in response to mike_west_australia

    i took my imac 27 late 2012 apart and changed the thermal paste. I had read someone say that was the reason for the heat problems and would fix the reset problems. I had installed macs fan control and could see the temp spiking just before the resets. Alas no luck.

    When i put the computer back together i attached the monitor screen with masking tape instead of double stick tape in case the paste didn't work. Then i saw this thread and decided to try the new power supply. Amazon sells the power supply (Liteon) for $65.97 with shipping. So i ordered it and got it today. Just installed and stress tested it. I test with high def video files at full screen. These seem to spike the gpu temps on macs fan control. Anyway it seems to be working. If i see another shutdown i'll report back.

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