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

Tomorrow I will go to take back my iMac 27 late 2012 from the Apple store here in Italy. It seems they have changed the power supply and the hard disk.

Let's see what will happen next weeks... but I am afraid that the problem will reappear...

This post has been seen more than 16000 times, how it is possible that Apple has not find jet a solution to this issue?

The computer has performed flawlessly since the power unit replacement. As I said before I could not get in touch with the guy that actually performed the replacement, otherwise I would have asked for specifics. All I can say is that I am quite sure that something was actually been done with the power unit, as the power button feels different now (a bit loose and sticking out a little bit).

Ciao.

Ho letto il tuo post.

Tu per caso usi un UPS? Vorrei capire se c'è qualcuno che ha rilevato gli stessi problemi anche utilizzando un gruppo ** continuità.

Un saluto.

Hello, I don't use a ups unit.

Do you have the same issue with an ups?

**************

Ciao. no non uso un gruppo ** continuità...

Tu hai lo stesso problema con un gruppo ** continuità?

Hi all,

I have been reading the thread for a few month now and it is really staggering to realise we all are experiencing a very similar problem, on so many level, and yet, none of us has a good grasp on the issue nor can share a reliable solution, which is appalling since we all requested help from Apple via the Genius repair service.

Yes, you may have guessed, I am affected by the issue too, since August 2015. Though not directly, as this is my dad computer, who bought the iMac as a retirement treat early 2013. Still, I am really upset by his experience as it is a source of stress whenever he uses his iMac and worst as it impacts family well being.

I agree with many points raised here, and from what I gathered:

Product: iMac 27inch (late 2012)

Observed: Random Shutdown - switches from normal usage state to unpowered state, in an instant.

Frequency: every 10-30 minutes at worse, once a day at best.

After shutdown, iMac can be switched on by performing SMC reset only, with a duration unusually longer.

Noticed, the longer the computer is unplugged, the greater is the running time before next shutdown.

No software cause detected, regardless of the application running, it can happen

• on any supported OS X
• on a freshly installed OS X
• even while installing OS X

No hardware cause detected,

• no over heating
• Apple hardware analysis reports nothing
• Apple Store service found nothing

And it still happens after changing:

• motherboard
• power supply (some said so in the forum, but waiting on Robert response below)
• hard drive
• memory
• power cord
• connected devices

No predictive element or pattern found, ruled out:

user house electrical installation (since several iMac are running fine in the house, even using the very socket of the failing iMac, and this one still shutdowns when plugged anywhere in the house, with or without ups)

Hypothesis:

• The hardware not yet tested are the machine structure and the screen, and they correspond in date to the introduction of the brand new super flat screen design(which is now the norm).
• The frequency of shutdown and the SMC reset time influence seem to indicate a phenomena of charge, which, when reaching a limit, triggers the shutting down.

There is a sane suspicion to believe that those two observations could be linked, and that investigating them would provide a lead.

Question to Robert Van Dongen:

You have had the power supply component changed only and since then have seen once the issue, is it correct?

If so, anyone here that did the same but who still experienced the issue.

Question to Joe5000:

Do you have any update, statement from the Apple Representative? (yep, they deleted the contacts you provided)

Question to anyone:

Is any of you engaged in an higher discussion with Apple and have a reference on the ongoing process.

As per the Apple brand, this is not a local issue (France in my case), how can this issue be addressed in a global context?

Please keep providing any update you would come across.

Thanks,

Answering your question: "You have had the power supply component changed only and since then have seen once the issue, is it correct?"

The logic board was replaced first, but the issue was not solved. The power unit (661-7170) was the second component to be replaced (on November the 26th) and the issue has not been seen since then.

Thanks a lot for your quick answer Robert.

Just waiting a bit to get some one confirming the same behaviour, or on the contrary, indicating that it solved the problem only for a while (not that I am wishing it).

I have had a power supply replaced on mine. Engineer seemed pretty convinced this was the problem. It's only a been a couple of weeks but no shutdowns so far.

Thanks for the comment, crossing fingers for you.

Just to know, how would you qualify the frequency of shutdown you had, once in an hour like or once a day?

If left unplugged overnight I would get 2-3 hours. Then after the first switch off no more than 20-30 mins max.

Ok, nice to read again confirmation of the behaviour.

Hopefully, changing the power unit (661-7170) is a real solution.

And in the worst scenario, if it is some kind of component to change every one, two or three year, as pain-full as it is, it is almost an acceptable deal (less than a 100 euros or dollars).

Still, I am willing to wait just a little more in case one come with on contradictory case.

Thanks again.

Laurent.d awesome reply here well done just putting all the problems and "attempted" fixes listed on one post is great. So here is what I have discovered after hours of phone calls and reading on parts. Spoke with a local Mac guy not at Apple store today near home and right away he said he wouldn't even open the 2012 or newer machines as they are too tight and tough to work on and recommended I have Apple do it which again would be fine if I trusted it would fix it but as we all know probably won't. So after the 8 months of having the issue and ****** as can right now I've decided today I'm going to try and order a power supply and tear down this EXPENSIVE paper weight myself, which BTW was off again when I got home this evening.....10th time this week.

My applecare has expired and honestly for the cost of the logic board, power supply and Apples Guru pricing etc its probably cheaper to buy a new machine at this rate so I figure why not attempt this repair myself as machine is really not worth much at this point and I'm determined to figure out whats causing this. I've ordered the tape for screen replacement and tools and will get the part this week and try the power supply first. It will not be the SAME model/version thats in it as I feel like even the replacement parts are junk which also may be causing the issue so why not try something different. Either way guys I'm going to attempt this maybe next weekend and will let everyone know how it goes after. If not I'm at a lose with this and its just crazy to me that Apple doesn't see what is happening here and offering to at least figure it out for us as most of us would be happy to get it fixed and pay but would like to know whats causing it and see them back it up.

Laurent, as I had posted, Apple decided to go ahead and give me a new machine. A 2015 5K model. After almost a year of suffering, I'm relieved. After replacing the power supply, and the logic board, the problem kept resurfacing. So I don´t think it was worth for them to try and repair it over and over again.

I know you've posted this before but if you dont mind, what was the year of the iMac that got replaced? Mine's late-2012 and problem surfaced 1.5 years after purchasing. Also, do you have Apple Care/warranty when you brought this to Apple.

Unfortunately same issues here with a late 2012 27". Last July it started shutting off, I spent 2 months of phone calls, chats with support, took it into the store and left it twice before finally after two months they replaced the power supply last September. Now four months later it's doing the same thing again. My apple care runs out next month so I'm no pleased that I spend $2300 on something that will be worthless. This is our family computer so I'm not too excited about the idea of having to deal with issues over and over again for the next few years. Any idea if this is something that happens on the newer versions? Or anyone have experience with Mac mini. I'm hesitant to get another iMac now.