iMac keeps going off

cazthebabe

macrumors newbie
Original poster
Mar 12, 2010
6
1
My iMac keeps going off like the plug has been pulled. Not sure if it was after the 10.11.5 update or not, but it does not re-boot automatically. I have to disconnect power cable then go through the SMC routine and sometimes it reboots. I have run an Apple diagnostic which has turned up no errors or faults.

It is driving me nuts! Anyone any ideas?

Some details:
27" iMac
El Capitan 10.11.5

Thanks
 

MCAsan

macrumors 601
Jul 9, 2012
4,557
419
Atlanta
Maybe time for a full OS reinstall. Of course only after making sure you have incremental backups such as from TM.
 

cazthebabe

macrumors newbie
Original poster
Mar 12, 2010
6
1
Hi, yes done that with 12 minutes left on the install it just went off again. Finally got it on again and finished reinstalling booted up as normal to virgin desktop and 5 minutes later it went again. Would not reboot without SMC. It switches off like the power has gone.
 
Last edited:

MCAsan

macrumors 601
Jul 9, 2012
4,557
419
Atlanta
Could indeed be a problem in the power supply. Definitely time for a trip to Apple Store or other authorized repair center.
 

JohnDS

macrumors 65816
Oct 25, 2015
1,183
248
What do the system logs say immediately before the shutdown? Your symptoms sound like overheating.
 

cazthebabe

macrumors newbie
Original poster
Mar 12, 2010
6
1
Hi, ended up taking it to Apple Genius and apparently it is the LCD display and they are going to replace it under Consumer Law. Thought I would let you know as you have been so helpful.
 
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