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

I see it a lot brighter now, so I'd like to give some hope to you, too. Firstly, with the amount of cases, the words "planned obsolescence" need to be dropped here. I cannot believe the immense efforts apple seems to go to not acknowledge that this series of iMacs has serious issues. Also, not at all replying to this gigantic thread made me get to the decision to leave apple products forever after using them exclusively for my whole life even before they were "cool". If some manager reads this, this is your doing and I will keep telling everyone I know, that Apple sells faulty (expensive!!!) products and does not stand by it but chooses to ignore their customers.

Sooo, now the advices:

I talked to someone on reddit with the same problem and he did some research: People that replaced the power supply are mostly happy now. The problem seems to be, that even the licensed workshop I'm going to because I lack any AppleCare does not simply want to replace it. They want to diagnose the problem and then make me an offer. 😟 Soooo, if you get your people to replace the power supple, then there is a chance you're fine, but getting them to do that might prove difficult. I'm very close to getting the parts and tools and opening that thing myself since, as you said, it's basically useless now.

As a short-time solution and kind of troubleshooting: Try disconnecting your iMac from power completely everytime it is shut down (especially during the night) and you should experience much longer uptime. If not, there might be something wrong with the mac outside of the power supply. So far it worked quite alright for me.

So about a week later after the Logic Board (and over a month the power supply was replaced as well) has been replaced, it shut down abruptly last night again, very frustrating.

I'm experiencing the same type of problem, but on a model ( imac 27' ) of late 2013

Despite the different release date symptoms are the same as those multiply exposed here.

It said in that thread that Apple takes the problem seriously, right ?

I found it hard to find information on the problem and to find confirmation that it is not an isolated problem

Hey guys. Count me in.

Same problem.

My iMac: 27" iMac late 2012 i7 3tb Fusion Drive Geforce 680mx

Started 5 weeks ago. First I thought it might be my hard disk. So I took my Mac to an Apple service provider. They changed my hard drive for free because there is a replacement program. So after I got it back everything was fine. But a week ago the same problem occurred again. Sudden shutdowns with no warning regardless of what I am doing. It happens when I play games or watch youtube or just do nothing.

So I took my Mac back to Apple Service. Of course they can't reproduce the problem I have described and they tested my hardware. Everything is fine.

After looking for a solution by myself, I came across this thread.

So there is really no 100% safe solution?

What a disappointment. And Apple seems to keep ignoring this serious problem.

Same issue here, started 2 months ago and I tried to wipe the HDD and start all over again. And am using a new powercord.

I guess the power supply is probably at fault, and I can only hope that Apple will acknowledge that there is a problem here.

iMac 27", late 2012, i5 3.2 GHz, 1TB Fusion drive, GeForce 680MX 2GB, bought in Denmark.

Hey guys, i have the same problem with my iMac ! It is a BTO with nvidia 680MX 2GB and i7 3.4. I took it to service but they couldn't replicate the random shutdown. I guess the problem is from the GPU or something related. My iMac doesn't shutdown surfing the web or in sleep, but in Adobe Lightroom or any more demanding GPU app the computer shutdown and than, when i turn it on again the problem happens more often. I can't do anything more than surfing the web check email or something light like that. I really don't know what to do, and i don't want to pay 1000€ for a new logic board, and it seems that doesn't solve the problem. Im in Portugal so we don't have apple stores here, just oficial resellers and some certified apple technicians.

Hey,

So, how is it going? So far so good for your iMac?

So my Mac is ready for pickup. Once again, they replaced the power supply and also the power supply cable?

We'll see how it goes.

To all the new cases: I've been error-free for 2 weeks now with disconnecting the iMac from power completely ⚠ everytime it's shut down. My sample size is daily use of about 4-6 hours in one piece or 2-3 hours twice with 1-2 hours of disconnecting in between. This is also the explanation why the tech support can never replicate the problem: It won't occur unless the iMac is connected to a power supply for more than a certain amount of time. To me this is the definite proof, that there is a power supply problem, but who knows... Perhaps this is just stalling, but let's face it: If I get another 2 years of usage out of my computer, it'll be the "normal" lifespan and after that, I'll buy a real computer without an Apple on it because I don't want to deal with this BS any more.

19 pages and still rolling.

I've had my iMac back from the Apple store now for a couple of weeks. It's had a second power supply replacement after the problem continued with the first one. My engineer was pretty convinced it was the power supply - my advice would be to definitely not shell out for a logic board replacement even if the Apple store recommends it. I'll update the thread if and probably when it happens again.

Hi All, I have the exact same issue with my late 2012, 27" i7 iMac with 1Tb Fusion drive. I sent it in for repair beginning of the year, but they could not replicate the issue. Once I got it back, it started shutting down again after some days, so I have now sent it back again as a repeat repair (also since my appleCare expired since then). I am determined to have it fixed, otherwise I will loose my claim on the support.

I wonder how I can make sure the support guys are able to reproduce the issue and if they can, how I can get an extra period of support for this specific issue?

Also, is there any support issue logged at Apple itself, so which I can add my case?

Sorry to hear that, but you seem to be out of luck: Since the problem pretty much goes away when you disconnect the iMac from power for some time (did not experience any problems after just un-plugging the cable everytime the computer is not on) and you have to send it in, you cannot get it into the workshop with the issue "still broken". I've read somewhere, that people are purposefully plugging it in for a week and running it until it pretty much shuts down at startup just before bringing it in to the Apple Store. Then it would shut down after 10-30 minutes there - depending on travel time. Perhaps that is an option...

Somewhere in this thread, someone mentioned that some Apple employee mentioned it is "a known problem now". BUT I highly doubt you can quote that and since Apple decides to ignore this thread in total my hopes of recognition from Apple's side are very low.

No new info here, just adding to the 19 pages of woe.

Machine shuts down randomly under both OS X and Windows ( El Capitan, Windows 7, and Windows 10).

Previous shutdown Cause: 0

(i.e. Power interrupted)

SMC must be reset to restore power to the computer.

As with all other folks in this thread, I've found there's a longer gap between shutdowns if the computer is left disconnected from power for a while.

Have tried:

1. Reinstalling OS

2. Removing and swapping all RAM

3. Disabling bluetooth and changing all peripherals (mouse, keyboard, external drives)

Specs:

Displays:

iMac:

<Personal Information Edited by Host>

Adding to the Saga....

iMac 27", 3.5 quad core, 8 Gb, 3 TB Fusion Drive, GTX 780M, refurbished 2013 model

Same issues with random shutdowns started mid 2015. Took it to Genius Bar who said it just need SMC reset.

That worked and I kept shutting down the computer every night. This worked up until last week while streaming video it shutdown.

Now I can't get it to stay on much more than 10 minutes.

As others have stated the longer I leave it unplugged the longer it will stay on.

I took it to Genius again and fortunately was able to reproduce the event while they were doing a HD test. It passed the first preliminary test.

I mentioned this thread and they suggested replacing the power supply. Unfortunately that did not work and now they are suggesting a replacement of the Logic board. According to this thread that has not helped and I declined the $900 fee to proceed.

Now contemplating just getting a PC again but interested to see if there is a solution.

It does seem to be consistent with a capacitor issue as doing a hard SMC reset and unplugging seems to give the longest reprieve.

Forgot to add to some of my other diagnostics

Console messages indicated shutdown codes of "0" if I unplug the cord.

Console message shutdown code "-128" if I restart without unplugging cord.