Level 1

51 points

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

Top-ranking reply

lisbonbhoy

Level 1

36 points

Posted on Oct 26, 2017 3:46 AM

Hi there - hope I'm on the right thread for this reply.

I recently suffered the same issue for over a week whereby my late 2012, 27" iMac (1TB fusion drive) would unexpectedly shutdown like someone had yanked the power supply cable from the back. I could only get it restarted by removing the power lead for 15 secs, plugging back in and waiting 5 secs before starting up - and apart from a Chrome "unexpected shutdown" message, you wouldn't have known that it had shut off.

I spent a few hours on to Apple Support trying various solutions (Diagnostic test, MemTest, SMC/PRAM resets, Sierra reinstall etc).

By trial and error, I eventually identified the problem's source as being my Satechi 7 port USB 3.0 hub which had 2 x Porsche design (1TG and 4 TB) external HDD's attached, along with 2 x charge/sync docks for iPad and iPhone. Since I removed the USB Hub and plugged the peripherals into the back of the iMac, I have had no issues whatsoever - and my pride & joy is back working like a dream.

I hope this update helps

View in context

574 replies

iForce_

Level 1

4 points

May 28, 2014 5:42 AM in response to giocal

Hi, in the end I brought the computer to the Apple Store and they changed the power supply.

It wasn't a software problem.

It was on apple care so I did't pay, but i was around 70€ I think.

Lagoiski Author

Level 1

51 points

Jun 2, 2014 8:45 PM in response to Lagoiski

Things I did:

1. Reformatted my iMac, clean install of Maverics

2. Bought a UPS

3. Switched my RAM sticks around

4. Did not install any google software like Chrome (those were seen in my log every time Mac crashed)

I know I should have done everything one at a time, so I have no idea which thing helped. So far has been working without any issues! If the problem is back I will update. Good luck fixing!

Lagoiski Author

Level 1

51 points

Jun 6, 2014 6:51 AM in response to Lagoiski

OMG! It just off-ed again! Gonna try to recall what I have installed today. 😕

Lagoiski Author

Level 1

51 points

Jun 10, 2014 6:43 AM in response to Lagoiski

2nd crash! Was downloading Xcode and watching some video tutorial in safari. Noticed a temperature warning from Temperature Gauge Pro saying its 80 degrees. Then suddenly poof and my iMac is down. Hmm, have a new theory to test, maybe there is a problem with wifi card that causes overheating. However my previos crash the temperature looked fine.

P.S. my old macbook pro stopped having wifi...... Did a fresh install of Mavericks and it does not even show the wifi as an option.

Lagoiski Author

Level 1

51 points

Jun 11, 2014 5:07 AM in response to Lagoiski

Ok, today I came home and my iMac did not start when I pressed the on button until I unplugged it to so the smc reset. It was shut down properly last night, so there is no way any software could have caused it. This looks more like a hardware failure to me, maybe faulty power unit? Running the hardware check does not show anything faulty though.

tphc

Level 1

17 points

Jul 19, 2014 11:04 AM in response to Lagoiski

Got the same problem as well - similar spec machine etc. My suspicion too is that it is a hardware fault - guess will have to take it back to Apple (out of warranty now though). Wonder if there are a bad batch of power supplies out there?

grw1988

Level 1

0 points

Sep 29, 2014 11:47 PM in response to tphc

Hi Guys

I've has exactly the same issue, sometimes up to 10 crashes in a day. Has anybody had a definite resolution on this issue? Thanks.

Dec 23, 2014 5:56 PM in response to iForce_

So has anyone figured out the issue of this problem yet? This happened to my late 2012 iMac 27 inch. about three months ago. Took it to the Apple store and they told me it might be a hardware issue and had to replace the whole logic board, which will cost me $700!!

@iForce_ did you resolve this issue by simply changing the power supply?

PatFont

Level 1

0 points

Jan 11, 2015 12:36 PM in response to Lagoiski

I have the same issue. Is someone has a solution? Do Apple read and help to solve the problems on their forum?

Jan 22, 2015 8:31 PM in response to Lagoiski

Hey guys,

hate to say it, but nothing you will do will fix this problem.

I have had it for more than a year, along with corrupting graphics. Random crashes. Try this. . . .When it happens next, when you first turn your computer on, try a PRAM Reset when it boots for the first time after the crash. I bet it crashes for you again before it can complete the PRAM reset. 😟

I have had my logic board replaced twice and my power supply once. Now the most recent fix, (logic board and power supply) has failed too and it's now crashing again after a month and half of being stable since the repair.

I just called Apple and they are replacing with a current model imac with same upgrades, honouring the upgraded processor and video card I had in there.n

The tech said on the phone that my call was pretty much going to make this become a "known issue". Get your replacement and don't put up with a buggy build.

Feb 9, 2015 10:44 AM in response to Lagoiski

Experiencing exactly same issue here... iMac 27 (late 2012) with 3.4Ghz i7, 16gb ram.

Random power fail requires SMC reset. I got power supply replaced by Apple Store but it starts again!

I wonder if this is fundamental design defect. I don't have Applecare so I had to pay around $100 for power supply. Now I don't know what I should do. I don't want to pay for logic board... Now I am trying to order new RAM.

Please let us know if you have found any solution for this situation.

Thank you!

Feb 15, 2015 6:15 PM in response to cre8ive.park

Similar problem here with my iMac 27 (late 2012) 😠. Bought and using Temperature Gauge Pro to control the fans (still shutsdown at times).

This model is a bad apple.

I spent over $2,500 for this computer and expected at least 4 years of untroubled usage.

Feb 15, 2015 8:39 PM in response to vanstar sydney

Update :

After the power supply replacement (cost around $100), the symptom came up again, went to apple store.

I was able to record the video. Also tried reinstall the OS through recovery partition but the power failed while installing Yosemite.

As expected, they recommended to replace logic board which costs around $770. Apple says it would be cheaper than buy new one. Are you kidding?? The computer was almost $3000 and does not run more than one year?? This is wedding gift from my wife which makes me so sad.

This is unacceptable... They told me only thing they can do is refund the cost for power supply.

Not sure what I should do... I really cannot trust Apple's hardware now.

I know the CPU in this logic board is detachable but the engineer says it is soldered. Why cannot just replace board only without CPU which I guess the reason of expensive cost? Even worse, they are not clear if this logic board replacement can fix the issue.

I don't want to pay more $770 for the $3000 machine which I cannot trust anymore, so exhausted. Even it can be fixed, I cannot use the machine with the feeling that it can blackout at any moment.

Feb 15, 2015 9:17 PM in response to cre8ivepark

Sorry to hear of your troubles.

I use mine in my work as a freelance photographer. While editing files in Adobe lightroom the computer just dies, then I loose all my recent edits - very problematic and costing me time and money. Seems to be overall poor temperature management.

My wife, myself and our 3 children, all use and love Apple products .. now, I am not so sure.

Looks like we got stiffed by Apple.

Mar 3, 2015 5:57 PM in response to cre8ivepark

Update 3/3/2015

I have replaced both Power Supply and Logic Board but the symptom is still showing...

Already tried with new RAMs before. Now remaining part is LCD display and CPU. (I've moved my original CPU from old to new logic board)

This becomes clueless. Not sure what I should do.

This thread has been closed by the system or the community team. You may vote for any posts you find helpful, or search the Community for additional answers.

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