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

Given the randomness of the shutdowns I am guessing everyone may experience a different length of needing to leave it unplugged.

Also I will be more than happy if apple truly has found the reason for my shutdowns but since it seemed to fall in line with this thread and a majority of late 2012 iMacs I assumed we all shared the same problem.

I could be wrong. It would. It be the first time.

I started with the same issues. Apple replaced the Logic Board and I used the iMac twice and it was good (2013 model) - today, it won't even start. Pushing the power button does nothing. Doing an SMC does nothing - and then out of the blue it started up by itself!!!

I ran tests etc - no issues, and let it just sit doing nothing - down it went fast and pressing the power button gets no response at all until the iMac feels like it.

Honestly, I feel very taken in by this model and am feared of ever getting another iMac again. I don't even want this one any more. Typing from the dark side 😟!

Note that Safari, Flash or any other browser use will reduce the alive time of your iMac....

today, I played OpenEmu only for about 9 hours without shutdown... disabling wifi and internet...

wifi and internet use a lot of power.

Well, finally i got my PSU, and installed it... has been about 4 hours since power up until now and my iMac is working like new.. no shutdowns... i pray to continue behaving like this..

will continue reporting...

I think all those people who changed logic board and psu, and still having the same problem, is because the new PSU they got is the same brand of Delta (the replaced one) . so they surely changed a defective psu to another defective one...

Thanks 🙂

From now, for everyone having this problem, don´t let it into store (unless your imac is under warranty)...

the easiest way is to buy directly the PSU.. this is which i bought:

http://www.ebay.com/itm/111714383449?ul_noapp=true

Hi, an update on my situation. Nothing has changed since my motherboard was replaced by the Apple authorized repair shop. System still crashes. Brought it back to the apple authorized repair shop, and they said there was nothing wrong with the computer. Couldn't reproduce my issue, they said. I told them explicitly about this thread. Nothing wrong with PSU they said.

******

<Edited by Host>

do you have exactly the same problem as us?... I mean, your iMac shuts down randomly and you can´t power up again unless you disconnect it from power source and wait at least 15 minutes.... is that your problem?.. because if that, then is 100% sure a PSU problem...

There is a way to reproduce it:

Use your iMac until shutdown, don´t remove the power supply cord, keep it connected to electrical source. Do this just before you get your iMac to the shop.... I´m sure they will experiment your problem in less than 1 hour...

Don't do it yourself. They replaced my PSU and Logic Board (second time for logic board) and so far so good, but I don't know what type of PSU they put in it. So far, so good, but who knows? It was good last time but didn't last. Mine did show it's faults to Apple, so I think that made it easier.

once you have opened it, then change the PSU is even easier... but of course, if your imac is under warranty, is better to take mind of this first...

Untill now, my imac works like a charm.. no shutdowns... has been one week since PSU changed... i´m happy..

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I can't believe this about Apple. I should have googled this a lot earlier. I've been dealing with random shutdowns (yes have to pull the cord and wait for the iMac to come back to life) for over a year. Left it with Apple in the summer for 2 weeks only to have them tell me everything is fine and it was a software issue. Lasted about a month. Started again. Bought new ram just in case. Same thing. Now it crashes more frequently.

Apple care over the phone is stringing me along. Today I believe at the end of my umpteenth call I heard the level 2 person handling my case giggle. "thanks for your patience".

So disillusioned with Apple right now. What happened to them? Especially their customer service??

13,2 iMac (late 2012), 3.4 i7. 680 2gb vid, 27", 32gb ram, 3tb fusion, $$$$$$$$$$

Same random powering off issues as original poster (Lagoiski) & manfromspace and so many other posters.

Puchased Late 2012 iMac from new in 2013, since that time the machine has required replacement of a faulty Logic Board, Screen, HDD and now a new PSU to 'suppodedly' remedy the random shut downs (time will tell, hopefully within the 90 days). Upon collecting the repair from the Cambridge store (06/02/17) I advised the Apple representative of this common ('manufacture') defect and this thread. His reply was he'd not heard of it and that effectively you'd find all sorts of negative comments if you googled the issue (despite the issue being extensively documented with this and other Apple Support threads). I was duly charged £148 for the 'potential' repair (again time will tell) before 'again' completing 'another' 80 mile round trip home.

The poor product quality experience of this late 2012 iLemon and customer service (x3 unhelpful phone calls) and current culture has definitely shaken my 24 years brand loyalty experience leaving me seriously questioning future computing purchases.

27 inch iMac (Late 2012) 3.2 GHz Intel Core i5, 3TB, 8 Ram, NVIDIA GeForce GTX 675MX 1024 MB

"seriously questioning future computing purchases"

I think many of us with this problem have this consideration, especially the cost of purchase taken into account. You would expect better service.

However, after 6 weeks my Mac is still running without issues after the PSU replacement.

Yep, hopefully the Apple fitted new PSU will resolve the previous defect. My machine although not being used has now been constantly on for 3 days and still going. However my concern is I don't know the brand of PSU removed and replaced. I tried to establish this with Apple Cambridge but no one wanted to speak (or listen) about it. Despite my being told by Apple Cambridge to call back to speak with the 'Genius' engineer that was dealing with it I was just put on hold twice for 10 minutes on 2 separate occasions only for the initial call taker to return restating what I already knew that it was a defective PSU - no one wanted to discuss any details of it! When I asked what brand of PSU had been used if Liteon or Delta I was just casually and randomly told by the intial call taker that it was an Apple brand PSU. In hindsight I should have requested Apple returned the faulty PSU to me (it's my property, I didn't say they could keep it) so I could at least added some further feedback to this thread.

Given this defective PSU issue, and the previously replaced Logic Board, Screen and HDD in this Late 2012 (purchased 2013) the faith and confidence I previously had in 24 years of Macs has now gone, I'm left with the uncertain feeling that this is not reliable machine nor a brand that I can ever really trully believe and trust.

Such a shame, Apple really needs to pick their customer service game back up!

Don´t be so bold, Mac computers are still very confortable !

they missed this little big issue, yes, but the solution is cheap... the problem is the Apple Center still does not know about this as an official bug...

Hi Lagoiski,

I got the same problem as you posted. iMac 27" late 2012, 1TB Fusion, nVidia GTX675. Random shutdown, SMC reset to boot it up. Problem started summer 2016. I also thought that it related to Adobe CC. Don't want to spend many hundreds of Euro's to repair it. But I can't sell it to someone with those problems. My Mac was 2 weeks at a repair centre and they found nothing. 😟

Did you solved the problem / found a solution?

Thanks.

Regards,

Bjorn