Turnip579
Level 1 (15 points)

Q: iMac 27 (Late 2012) Shuts down. #2


I have a LATE 2012 iMac 27".

About a month ago, after very little use the computer started shutting down. It just turns itself off. No given time, just sporadic. After reading tons of other posts on this same issue, I am at a loss as to what the problem is. All the other posts gave POSSIBLE causes and these go all the way back to 2008. I took the computer to the Apple store in the mall and they said they would order a logic board and that because this was a "high end" board, it would be $800. I can't afford that after spending thousands on the unit and cannot find a solution online.There are numerous "guesses" as to what the problem is. RAM, power supply, logic board and a few others. I'm at a loss as to what to do. The computer just shuts down at random.

   I have replaced the power chord. Ran power to different sockets, Switched the RAM that it came with around (4 DIMMS) to see if I have a bad module. Ran all the diagnostics that I could find on this site and it says NO PROBLEMS DETECTED. Reset the SMC numerous times, tried to update the firmware but as luck would have it, there is no update even listed on the site for MY MODEL.
Any help would be appreciated.
My Specs:
27-inch, Late 2012
Processor  3.4 GHz Intel Core i7
Memory  16 GB 1600 MHz DDR3
Graphics  NVIDIA GeForce GTX 680MX 2048 MB
Serial Number xxxxxxx
Software  OS X 10.9.5 (13F34)
Model Name: iMac
  Model Identifier: iMac13,2
  Processor Name: Intel Core i7
  Processor Speed: 3.4 GHz
  Number of Processors: 1
  Total Number of Cores: 4
  L2 Cache (per Core): 256 KB
  L3 Cache: 8 MB
  Memory: 16 GB
  Boot ROM Version: IM131.010A.B05
  SMC Version (system): 2.11f14
  Serial Number (system): xxxxx
  Hardware UUID: 29520205-A76A-54AE-9DA2-4378AADDCF19

iMac

Posted on Nov 6, 2014 1:08 PM

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Turnip579

Q: iMac 27 (Late 2012) Shuts down. #2

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  • Helpful answers

  • by goonerdavem,

    goonerdavem goonerdavem Dec 27, 2014 10:46 AM in response to Turnip579
    Level 1 (0 points)
    Dec 27, 2014 10:46 AM in response to Turnip579

    Do you still have this problem?  I have (had?) a similar symptom where the computer would shut down and it would take a SMC reset to get the computer to re-start.  Annoyingly when I took it back to be repaired (twice) the service centre couldn't find anything wrong and I've been trying to work out what is different with my home set-up compared to there's. 

     

    My answer to that was that they always used a wired keyboard and mouse when testing my unit and sure enough, if I turn off Bluetooth on the computer and revert back to a wired system the crashing stops.

     

    Do you use a wired keyboard and mouse?  If not, are you able to test your computer with a USB rather that Bluetooth set-up.

     

    This doesn't explain why the problem happened but it might at least give you something to work on.

  • by Turnip579,

    Turnip579 Turnip579 Dec 27, 2014 11:05 AM in response to goonerdavem
    Level 1 (15 points)
    Dec 27, 2014 11:05 AM in response to goonerdavem

    My problem we the power supply. $100 repair. Since replacing it, everything is fine. I tried using a wired mouse, but it still shut down. Taking it to The store , they were able to see it sbutting down so it wasn't the Logic board which would have been 900 bucks. Good luck

  • by RubenBCN,

    RubenBCN RubenBCN Feb 20, 2015 1:11 AM in response to goonerdavem
    Level 1 (0 points)
    Feb 20, 2015 1:11 AM in response to goonerdavem

    I have the same issue and I also took it twice to the genius bar. They couldn't see it shut down (they kept it just 24h) so they didn't fix it.

  • by Fametown,

    Fametown Fametown Feb 20, 2015 3:18 AM in response to Turnip579
    Level 1 (4 points)
    Feb 20, 2015 3:18 AM in response to Turnip579

    Hi !

     

    Same problem here. iMac 27" Late 2012 with 3.4Ghz. 8Gb Ram. Nvidia GTX 680MX. Ramdom shutdows. I can have more then 7-8 in the same day. 4 times in official service but they can't reproduce the problem. ¿?¿?¿?

     

    Thanks!!!

  • by floydturbo,

    floydturbo floydturbo Mar 23, 2015 1:56 AM in response to Turnip579
    Level 1 (0 points)
    Mar 23, 2015 1:56 AM in response to Turnip579

    I have had the same problem.  I took it into the Genius Bar and they replaced the power supply, which fixed the problem for about a month and now it is shutting down again.  This seems to be a somewhat common problem with this version of the iMac.  They will probably recommend replacing the logic board next for around $1,000.  At that point I may just decide to take my losses on this computer.  I'm very frustrated as this is my first Mac and I dropped about $3,500 on a fully loaded machine and it looks like it will only last for about two years.  I'm not sure if I am in a hurry to replace it with another Mac.

  • by RubenBCN,

    RubenBCN RubenBCN Mar 23, 2015 2:16 AM in response to Turnip579
    Level 1 (0 points)
    Mar 23, 2015 2:16 AM in response to Turnip579

    I have had unexpected shut downs for 3 months. Since December (when the computer was 2 years old aprox.).

    As I stated above, after visiting 2 different Genius Bars where they could not fix it, this is what I have accomplished in order to keep using the machine with no shut downs.

     

    I usually had multiple shut downs on a regular day. Sometimes after 2h, sometimes after 7h. When that happened, I needed to unplug the iMac for 15 minutes (I ended up calculating with iOS Timer).

    So I though maybe there is a component being charged unexpectedly until the mother board shuts down itself for security. That would explain why changing the Power Supply doesn't work.

     

    Anyway, I decided to connect the iMac to a multiple power socket with a switch. When I'm done working with the iMac, I shut it down and I also switch off the power socket.

    Doing that seems to "uncharge" whatever was going on in the iMac as when I come back to turn on both socket and iMac I can work with it for more than 24h.

     

    I've had no shut downs for 3 weeks now. And after having 3-4 shuts downs every day., this is something.

  • by red.m.aciej,

    red.m.aciej red.m.aciej Jun 3, 2015 7:45 AM in response to Turnip579
    Level 1 (0 points)
    Jun 3, 2015 7:45 AM in response to Turnip579

    Hello,

     

    have you tried to install 4 memory modules on your iMac? I have exactly the same model and I cannot make it to work with more then 2 modules installed. Please take a look at my thread:

     

    iMac13,2 27" with firmware from 21.5" not seeing the 4 memory bays

  • by RubenBCN,

    RubenBCN RubenBCN Jun 3, 2015 8:35 AM in response to red.m.aciej
    Level 1 (0 points)
    Jun 3, 2015 8:35 AM in response to red.m.aciej

    This might be slightly off topic but yes, I have my 27" iMac running on 4 modules of 4GB each.

  • by red.m.aciej,

    red.m.aciej red.m.aciej Jun 3, 2015 9:00 AM in response to RubenBCN
    Level 1 (0 points)
    Jun 3, 2015 9:00 AM in response to RubenBCN

    Thank you very much for the answer. You have exactly the same firmware like me which seems to prove that it's not the firmware issue.

     

    At least I will save some time on searching for a different firmware