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

I'm very curious that you seem to have come across a solution where everything else has failed. Forgive my skepticism however, in all the research I have done regarding this known problem, I have not once come across BGA re-balling as a potential solution. Are you able to provide some links to examples of where this has been successful on imacs?

You have every reason to be skeptical. However, Apple mods seem to be a little touchy about this topic, and even providing links on this subforum page can lead to warnings and bans. After all, we're not talking about Apple certified repairs.

However, you can find information and services outside this forum.

Forgive me, if I am getting this wrong, but if BGA re-balling is the ultimate solution to this kind of problem, then why people who have their logic board replaced still having the same problem.

That's hard to say. But it makes sense that, if a logic board is being replaced repeatedly without good results, that fix isn't working.

BGA re-balling is different than replacing a logic board. It involves meticulously desoldering and desoldering surface-mounted electronics under controlled conditions.

My thoughts exactly. If melting and re-setting the solder on the logic boards fixes the problem, then why wouldn't a brand new logic board also fix the problem? Is the suggestion that the soldering on all Apple logic boards is defective?

I can understand that this may be a sensitive issue, but I simply cannot find any reference to instances where this has worked on an Imac. I've seen it mentioned as a fix for MBPs, but with other issues directly relating to situations where logic boards are clearly fried.

Has anyone on this thread tried re-balling as a solution?

From all the people with the shutdown issue, has anyone come up with a solution or had a fix from Apple that has solved the problem yet, or have people given up?

I'm thinking of escalating this to a higher level with Apple, has anyone else tried this course of action?

I have little new to add (I've posted earlier on this thread with the same issue as everyone else). I've had to buy a new computer (a refurbed trashcan) so that I can keep working and my iMac has now been relegated to paperweight status. I think I'm done with iMacs for professional use - they aren't reliable enough.

I had hoped I might be able to keep using it as a display for the new MacPro in target display mode - but even in this lowly task it randomly shuts down. It now takes longer to get it going again as well. Previously pulling the power, waiting 10 secs and rebooting was enough - now it needs several hours or even over night before it will switch on again - which must be heat related, right?

This needs an official response please Apple. Start twittering, people, let's make some noise.

It's just tragic that we are faced with the reality of purchasing new computers to replace a defective run. Really not fair at all and horrible customer support from Apple, which will ultimately damage their business/reputation.

And they make it really hard to complain - I want to escalate the issue in terms of consumer rights, but I'm having a really hard time even getting to talk to anyone other than low level sales consultants or tech support staff. I'm sure there's someone out there who has it in their job description to actually do something about this.

As with all defective runs, the problem seems to be very specific with possibly certain batches. I wonder if there is any way to tell what 'batch' these defective models came in? I have a late 2012 at work that gets heavily used every day for video editing and that has always been fine, whereas my home computer (that I also used to use for work purposes) is unusable. The only difference I can see is that they have different video cards and mine has more RAM than the work one.

I also wouldn't write off imacs in general for heavy use, I sometimes work at a university where they have labs full full of late 2013 27" imacs which get thrashed day after day by students doing video editing, grahics and 3D, which have worked flawlessly without any shutdown issues.

I'm really not convinced that it's heat related, mine will shutdown at night when it's cold and in sleep mode. I've even shut it down properly and had it require an SMC start of unplugging for 15 minutes.

Making noise is a good idea, but this should be backed up with making calls to the right person and formerly complaining. If anyone has any luck finding a contact who is high enough up the food chain to actually take notice, please let us know.

I agree about the heat issue as well as I've also encountered shutdowns that were either in sleep mode or when the iMac had just been powered on in the morning. For what it's worth I am still under Applecare and passed this forum along to the customer service agents that were assigned to my claim. Unfortunately for me I tested out the idea of leaving the iMac unplugged overnight and haven't had a shutdown since I last talked with Applecare about two weeks ago. Because of this I'm more or less waiting for the problem to resurface so I can "prove it." Hopefully we can figure this out collectively and those of you with unusable units can at the very least pinpoint the issue and salvage your iMacs and your sanity.

Dears,

It seems that installing a power switch in between the iMac and the wall plug is the solution, as mentioned earlier in this thread: since I am switching that power switch off after each time I power off the iMac, all symptoms have disappeared. I haven't experienced another unexpected shutdown in the past 3 months.

This was my approach for the last few months. It definitely helps though it is not a definitive solution.

I've been using a switch since March (I commented before on this thread) and that helps but still I get shutdowns from time to time.

Suddenly there is a week when it constantly shuts even if it is disconnected all night through the power switch.

Also this prevents you leaving the computer all night processing something which is a non-sense we just accept because Apple still has not addressed this malfunctioning.

I have the same experience.

My iMac just randomly shutdown. I have tried all different solutions, non of them work.

I took the iMac to genius bar, but they say no issue, and the auto shutdown issue is not able to replicated in the store.

I was very disappointed. Unfortunately, I do not have Apple Care, and warranty is expired. I am not sure what can I do.

The main problem with a random shutdown is the randomness.

Documentation is crucial if you have this problem. Note every time it happens: the time, how long you've been using your computer, and what you've been doing, Since you may not know what the basic problem is, it's important to get as much detailed information as possible.

If it's a power supply problem, this documentation is particularly important. Power supply problems are predictable; if a machine is on for five hours, then shuts down, the next shutdown will be under five hours. Keep your machine powered as long as you can to capture the time intervals. And if you're going to the Apple Store, keep the machine powered long enough so the power supply shutdown happens when the Apple employee is there.

And of course, post here with your results.

I have just gotten off the phone from a long conversation with 3 warranty claims representatives from Apple asking for a replacement for my imac under consumer law. It was sounding reasonably positive, but the main flaw in my case is that I haven't had the power supply and logic board replaced by an authorised apple repairer, such as many others have. It's hard to articulate (even citing this forum), that the power supply and logic board are not the issue here; it's simply a defective model. I'm really hoping I don't have to go through the tedious and expensive process of getting these things replaced just to have a shot at a replacement computer. Hardly seems worth it, it would probably be cheaper to try and get a replacement under insurance.

In terms of documenting the issue, I can definitely concur that the amount of time I can get the machine to run without shutting down is approximately equal to the amount of time I leave it unplugged for. If I leave it unplugged overnight, I can usually get a day's operation out of it before it starts shutting down again. Once it's shut itself down, leaving it unplugged for only 15 seconds will guarantee another shutdown within the hour and even more frequently after that.

I would suggest others calling Apple warranty claims - especially if you've had an authorised Apple repairer replace the logic board and/or power supply, which should be documented on their system. It would be nice to see some us get a new Mac out of this.

Thus far, I feel like Apple are on my side, but for them to do a recall of any product they need to know that it's a clearly documented problem. If people don't call them and make it known that certain batches of this computer are defective, they will treat it like an isolated incident. They're getting me to take mine into an authorised repairer to run diagnostics confirming that it randomly shuts down. I'm confident the computer will behave itself (or not behave itself) and perform true to form for the experts. What I really don't want to have happen is for Apple to simply pay for a repair, like a new power supply etc, which we all know will not fix the problem. I want a new computer that is not a dud.

I really think it would be in all of our best interests to call Apple and make this issue known - especially those of you who have had the repairs done to no avail.

I do think that Apple are a fair company and try their best to address consumer complaints, as can be seen by actual recalls and refunds, but they need to know there's a problem. And this won't come from a bunch of people on a forum thread.

My iMac 27 (Late 2012) is also having the same problem. The screen goes black and no longer responds to the keyboard, mouse or power button. Only way to make it work again is to do a SMC reset.

In my case, the problem started about one week after I updated El Capitan to 10.11.1.