Late 2013 iMac shuts down/loses power randomly

[sppunk]

For the last week my late 2013 27" iMac (fusion drive fwiw) has several times when in use shut down entirely. It's like the plug is being pulled, just poof. It isn't just the display, the connected USB drive dies too.

When it happens the power button doesn't work. You can hold it for mnutes, push it once, whatever and the iMac won't power back up. To get it to restart I have to physically unplug the plug from my surge protector and plug it back in. I've tried multiple outlets with the same results.

Today it has happened 7 times so far, by far the worst yet. There is no rhyme or reason to when the shutdowns occur. I've had it happen when sending an iMessage, using Firefox, browsing a file folder, watching a YouTube video, etc.

I have AppleCare and called this morning but wasn't really helped much. He had me flash the RAM and said since I can't reproduce it with an action there wasn't anything he could do.

An ideas what might be causing this? There have been no changes to the machine, it's entirely up-to-date, and doesn't have any crazy apps or anything. Just standard Adobe CS, FileZilla, TextWrangler, etc. Nothing rare.

Thanks for any advice!

 

[MCAsan]

Take it to the nearest Apple store or authorized repair center.

 

[DeltaMac]

I suspect that your power supply is failing.
Yes, The AppleCare tech that you talked with really can't do anything (can't fix it over the phone )
Take it to an Apple Store, or an authorized service shop, if you have one local to you.

 

[sppunk]

Take it to the nearest Apple store or authorized repair center.

I suspect that your power supply is failing.
Yes, The AppleCare tech that you talked with really can't do anything (can't fix it over the phone )
Take it to an Apple Store, or an authorized service shop, if you have one local to you.

I was afraid that'd be the only real solution. The nearest is 50 minutes away and I can't drive. I can get a ride so no huge issue, it's just a bit of a pain.

At the store if it doesn't crash what is the solution? I can easily see it not crashing there and they think I'm nuts. Can they look at any diagnostic and see that it occurred?

 

[DeltaMac]

The "shutdown" will likely be listed somewhere in the system.log, available for viewing from the Console.app
Or, it should be showing as a reported "previous shutdown code" with a number after it, again in the Console.
The Apple store should be able to sort it out for you.
Be certain that you mention that it is shutting down more often now, sometimes multiple times a day, and power goes completely off.
You may need to drop it off so they can test it. Should be a power supply, but certainly could be a logic board problem of some kind. A good tech can get you sorted out.

 

[ohmyggg]

You are most likely experiencing this frustrating issue: https://discussions.apple.com/thread/6176570?tstart=0

...an issue with no solution that people have been complaining about and calling in about for 2 years, one that Apple has chosen to completely ignore.

I encourage you to read it but the TLDR version: OS reinstalls, RAM reseats/swaps, unplugging peripherals, and changing hardrives are what Apple will recommend. None of that will work. Then they'll recommend that you replace your power supply and/or logic board. Neither of those will work. People have had multiple power supply replacements and the random shut-downs always come back after a few weeks/months. If you're on Apple Care, they'll obviously pay for the fixes, so all you're wasting in that case is your own time, but people who don't have Apple Care have actually forked over hundreds of dollars in failed repair attempts. There is simply no solution.

I think I recall reading 2 cases on that thread in which people had their iMacs replaced with a new retina version, but not after a lot of fighting and/or 3 consecutive failed repair attempts. For those who are off Apple Care, good luck paying for 3 failed repair attempts out of pocket (especially considering a new logic board is like $1000).

The one temporary fix people have discovered is that if you unplug your iMac every time you're not using it, it will run longer without a shut-down the next time you need to use it. So, there's a correlation between uptime and time disconnected from a power source, which leads most people to believe that the issue is power supply related, yet replacement power supplies fail to fix the problem, so Apple seems to be replacing defective power supplies with defective power supplies.

Sorry to sound like such a downer. I've been experiencing the same issue for a year and it kills me that I spent over $3k for a machine that is straight up defective. My Apple Care is expired, so all they could offer me was some general advice over the phone about reinstalling OS X and disconnecting RAM and peripherals. Otherwise, their suggestion was to make a genius bar appointment (which, according to everyone else's experience, would lead to a recommendation to buy a new power supply and then a new logic board). It's just crap. Sorry.

 

[sppunk]

Well that's troubling to read.

It lasted about three hours without a shutdown until a few minutes ago. I made a Genius Bar appointment for Sunday. Now to carry it through/across a giant mall, weeee!

I have AppleCare+, we'll see how it goes.

 

[MCAsan]

If you are really lucky, they will replace it with a new 2015 iMac.

 

[ohmyggg]

Let me know how it goes. Fingers crossed they set you up with a newer model replacement.

 

[sppunk]

Let me know how it goes. Fingers crossed they set you up with a newer model replacement.

I took it in yesterday and the genius rep saw all the 0s in diagnostics. It is there waiting on a power supply he ordered. He said they'll run diagnostics on it too until it crashes.

I'm shocked they don't have power supplies in stock but whatever. He gave me a 3-5 day turnaround estimate.

 

[ohmyggg]

I took it in yesterday and the genius rep saw all the 0s in diagnostics. It is there waiting on a power supply he ordered. He said they'll run diagnostics on it too until it crashes.

I'm shocked they don't have power supplies in stock but whatever. He gave me a 3-5 day turnaround estimate.

The power supply replacement should buy you some time (hopefully more than some!), but many of the reports haven't been good. Looking forward to hearing how it all works out for you. Best of luck!

 

[sppunk]

Update: been 9 days since repaired and have had zero power failures. Yay.

 

[Lnkn52]

Update: been 9 days since repaired and have had zero power failures. Yay.

I've been one of those unfortunate iMac owners with the same power issue. It started all this year. Literally went 4 times before they finally replaced my iMac. I've gone through Logic Board, Power Supply and Power Supply cable replacements.

I also have kept up with that Apple Community thread and I'm sad to see that even newer models are having the same issue. Purchasing another round of Apple Care for my new iMac.