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

Ok, next update...

So I've had the iMac back for nearly 3 weeks now with no recurrence of the shut downs....that is until today :-(

It has repeated exactly the same shut down as back in Nov 2015. So a call to Apple and the outcome is to take it back to my local Apple Authorised dealer for testing and a (possible) power supply/power cable replacement.

Now this all sounds very familiar I hear you say but at the moment I suppose I have to try all the options until there is none left.

So here goes and the 5th attempt to sort my ailing iMac out.

Ill let you know how I get on.

Cheers ;-)

Mine is a late 2014 machine and its doing the same thing!

iMac (Retina 5K, 27-inch, Late 2014) 15,1

3.5GHz Intel Core i5 with 8GB of stock memory

AMD Radeon R9 M290X Graphics

El Capitan 10.11.3

I dont have anything attached to the machine and I am using all stock programs. I used it 90% of time for just light surfing using Safari. Viewing photos is my other "work". I am not editing mind you, just viewing them using Preview.

I bought the machine around Feb 2015. I didnt start to use it till June 2015 as I was moving house. Problem started in Jan 2016. Since then it has happened for about 7 to 8 times. Thrice, when it happened I was looking thru a bunch of photos. Twice it died when it was in sleep mode. Once I was surfing using Safari. It can happen a week apart or few minutes after rebooting (yes have to reset SMC first each time). I dont think its dirty or its a heat issue. It doesnt feel hot to me, not even warm.

I have not got Apple to replace anything. Just Chat with them doing some resets which is obviously useless. My warranty is expiring in 9 days LOL.

My first and last iMac. 😟

Thanks UKscottyGB for sharing,

can you tell us what they did in the first repairing session?

HI,

the iMac was kept for a week to run tests. After chatting with the engineer he reported that the main logic board had developed a fault, (he did not specify what the fault was), as a result the board was replaced with a new one. The Fusion Drive was wiped clean & the OS was reinstalled. The iMac has shut down again twice today without warning so the conclusion must be that the logic board as not causing the problem. I'm hoping to take it not my local Apple dealer this week to run tests on the power supply + cable. I'll or you know how I get on.

Well, it's ridiculous for Apple to handle these kind of malfunctions in such poor and dodgy way. I bought my first Imac in 2006 and is still running even if it had the superdrive broken twice and a stain on the monitor, all the time the machine has been repaired for free. Now these machines are broken after 1 or 2 years and Apple does not care. Shame on you Apple!

UkscottyGB, please tell us how you get on with next round at the genuses, I heard that it might be a faulty Power Supply board, the capacitors in particular. Hope you solve your problem!

Hello everyone out there.

- I love ( and hate ) this thread and i'm hit a 100% with this problem.
- Please stop local diagnosing. The core to this problem is a malfunctining hardware component ( probaply a malproduced capacitor

on the PSU ), but Apple knows..... Come one, please tell us, so we need to know, what is to be replaced????????
- Servicecenters can't replicate the problem. WHAAAAAAAAAAT..... I can do it every day and it is very consistent. I just have to

leave it turned on and it happens.
- Bootcamp or not. Problem is totally the same!!!!!
- A non-detectable heat issue that is actually logged!!!!!!!!!!!! Hardware problem!!!!!!!!!!!!!!!!!! Apple know's exactlyhow to interpt logs..... and how not to!!!!! I don't think this is a controlled shutdown ( or whatever one would call it ), due to heat!

I have to pull the plug physically for 10+ minutes... otherwise I can't turn the computer on again.
- Apple? Please respond!!!!!!!!!!!!!!!!!!!!!!!!!! Tell us what to do?

I have a lot more to say about this issue, but I'll keep it short. Apple needs to respond!!

APPLE KNOWS TOTALLY WHAT THE PROBLEM IS!!!!!. When did silence become the order of support?

... PS

So I got my motherboard replaced 2 weeks ago by apple, the problems just came back, PC crashed same Kernel error. I'll go back to apple store sometime soon. -__-

I've got my iMac back with a new power supply board fitted & replacement power cable. It's been running for 3 days now & has not shut down once. I had it repaired at my local Apple Authorised Service Dealer (not at Apple Genius), who have been gr8! They ran hardware diagnostic tests on the repaired iMac & could not find any faults. I have to be fair & say that Apple have repaired the iMac each time it's developed the (same) fault but my confidence with this particular iMac running fault-free is low.

I will keep you updated if the fault reappears or indeed if it completely disappears.

This thread has been invaluable. I have this same late 2012 model. Bought second hand in 2013. Thank you everyone for your advice and tips. I took my Mac to the Apple Store last week. Following advice from this thread I made sure my Mac had been running all day before I took it in and I had a diary of all the times it shut down - last time was one hour before my appointment. It actually shut down during a diagnostic at the Genius Bar. With no arguments, no warranty and no Apple Care they replaced the logic board (graphics card is integrated on this board the Genius informed me) and I paid for a new hard drive which showed a fault. We agreed the HD fault was a separate issue. Because of UK consumer law I did not have to pay for the logic board and labour. I felt the service was excellent and was really pleased.

That was the good news. The bad news is that the same fault happened again last night – twice – after having been on for three days mostly in sleep mode. Going back in on Saturday to discuss it again, with my new diary entries of shut downs/power-offs.

Robert van Dongen has replacing the power unit done the trick for you?

I can't speak for Robert, but after four trips to the Apple Store, one futile logic board replacement, two futile hard drive wipes and finally a power supply replacement, the iMac hasn't shut down on me. I'm still slowly ramping up the work I do on it, but at least it's not instantaneously shutting down as it had before. I'm still horrified that even though it hasn't shut down yet that the defect is still present and just working its way through amother power supply.

I'll keep everyone posted but thus far the power supply replacements have had the best immediate results. Furthermore I've informed every Apple rep of this thread though none have taken much interest in it. I'd advise you all to do the same.

Thanks everybody for keeping us posted.

So the bad capacitor theory is gathering some steam, and this is comforting somehow.

Apple are you there??? Can someone give us some support on this?

Similar problem except the shutdown happened only once and the iMac never recovered. Had to change the logic board which is costing me $500+. How can I trust Apple after this? This machine has Apple's HW and Apple's SW. So why the heck should I have to pay for their faulty build? This *****!

The whole premise of Apple products being expensive and non-repairable is based on controlling the HW and SW, to provide a great user experience. So when it fails, Apple has to OWN the full responsibility and replace the system - no questions asked.

Krishna

Same problem, same make, model and year. Had it to Apple three times. Like others, they were unable to replicate even after keeping the unit the third time for a week. I told them to look at these threads so they'd acknowledge it is not an isolated incident. In their infinite wisdom the Genius Bar started to blame my home office setup and wanted me hire an outside consultant to review it. As if I or any of us need someone to look at how we plug in our Macs! It was actually quite insulting. I've checked the power at the moment of shutdow at both ends and there is no and never was an interruption. Funny thing, after the third visit the problem vanished for a few months but now shows up nearly on a daily basis. This makes one wonder if the simple act of physically moving the machine causes something to happen to temporarily resolve the issue. This could explain partially why so many of us have taken out units in with Apple unable to replicate the problem. Seriously does anyone know a good class action attorney? Apple avoids any comments here or any official acknowledgment as they certainly realize this could lead to a costly recall and bad PR, God forbid! I'm checking with the FTC. Something needs to be done to make this right for us!

One of the things we seem to have discovered on this thread, and that allowed me to finish a project on the iMac before taking it in for repairs, is that if you unplug it for an extended time, say overnight, it usually stretches the amount of time that the iMac will run before the problem resurfaces. I think this could be the issue you dealt with. It also seems common that this fix only works for a while and the interval time before shutting down reduces over time.