Late 2012 iMac 27" i7 3.4 died; where to start??

bonedaddio

macrumors member
Original poster
Jan 23, 2009
62
0
PA, USA
Tried disconnecting all peripherals and the hold the power button thing, then the plug in the power cord while holding the button thing.; nada, zip, zilch, no sign of life.
This may be from an electrical storm; the iMac is on a good surge suppressor, and it's companion Dell 30" monitor is fine. When I left, it worked; when I came home, it was dead.
It's out of warranty; I'm fully capable of taking it apart, fixing it etc. So, take it to the Apple Store or buy some specialized tools and have at it?? Any thoughts or suggestions welcome!
 

ravinder08

macrumors 6502
Jun 11, 2010
291
40
I would definitely call Apple.
Apple's customer serve is legendary and I think if you spoke to them they will do their best to fix the machine.
 

bonedaddio

macrumors member
Original poster
Jan 23, 2009
62
0
PA, USA
Based on other research, I unplugged everything from the iMac, and let it sit alone, cold, and dark overnight.
I held down the power button, plugged the cable in (without much hope, sure seemed dead in there!) while still holding the power button, and the fan kicked in on high, and the screen lit up, etc...
I then turned it off, hooked everything back up (I boot off an externall SSD on Thunderbolt), booted up normally and we're off and running!
Wow.
Does anyone know much about the ins and outs of this? It's a little frightening.
Is there anything else I should be doing, like resetting SMC or something?
 

soupcan

macrumors 6502a
Nov 21, 2014
732
2,926
Netherlands
That's weird. Maybe it did have some random surge in the machine, which usually only goes away when you unplug it for a while. If resetting the SMC makes you feel better, it can't do any harm, so go ahead.
 

macthefork

macrumors 6502
Feb 2, 2013
467
7
Sounds like you already reset the SMC by unplugging it over night. Although, the correct way to do it is:

Shut down the iMac
Unplug it
Wait 15 seconds
Plug it back in
After 5 seconds press the power button to start the computer
 

Samuelsan2001

macrumors 604
Oct 24, 2013
7,682
2,103
Based on other research, I unplugged everything from the iMac, and let it sit alone, cold, and dark overnight.
I held down the power button, plugged the cable in (without much hope, sure seemed dead in there!) while still holding the power button, and the fan kicked in on high, and the screen lit up, etc...
I then turned it off, hooked everything back up (I boot off an externall SSD on Thunderbolt), booted up normally and we're off and running!
Wow.
Does anyone know much about the ins and outs of this? It's a little frightening.
Is there anything else I should be doing, like resetting SMC or something?
Could be a glitch with booting from an external drive, that would be my guess, it's always a possibilty with using that method.
 

DeltaMac

macrumors G3
Jul 30, 2003
9,525
2,298
Delaware
Yes, what you did is pretty much an SMC reset. You don't need to wait overnight. As macthefork said, all you need to do is unplug everything, leave it alone for 15 seconds or so, plug back in. Wait about 5 seconds, and turn back on. That IS an SMC reset.
I suspect that if you had a (brief) power outage, then that's the culprit. The logic board sometimes will lock up as a result, and the short SMC reset will fix that. And, a "surge suppressor" doesn't do anything if the power simply goes off.
And, your best bet (in an area that might be prone to power outages/brownouts) is an actual UPS.
 

vanstar

macrumors newbie
Jun 30, 2015
1
0
Sydney
A heads up on many 27" iMacs (late 2012 in particular) with various issues - Random shutdowns, screen tearing, flickering and shutoff etc..

Official Apple support communities (Admin) are locking the threads and deleting posts - Big Brother Syndrome.

My late 2012 i7 has experienced random shutdowns for the past 6 months. I have just bought a new $3000+ macbook pro so can now bring my iMac in to the geniuses (?).

Please check the iMac intel threads on the official Apple support communities.

A few sample threads:

https://discussions.apple.com/thread/6176570

https://discussions.apple.com/thread/3867688?start=0&tstart=0

https://discussions.apple.com/thread/2330035?start=300&tstart=0

- We have created this petition for Apple. At least it might tell us how many people is affected by - - this:

https://www.change.org/p/apple-resolve-random-shutdowns-on-27-imacs