2015 IMac 27" Retina Display Random Shutdown, Logicboard Changed by Apple Store $640 and again same.

[MacLemon91505]

Imac 27inch Late 2015, Random Shutdown, Apple Store Charged me $640 and the same issue happened again, took it back again and they said it was probably my cable, and reformatted my hard drive wiped everything off and gave me a cable (Made a Exception) and 2 days later it shutdown again.

This shutdown can not be powered back again from the back, the wire has to be unplugged and plugged in and start again.
They keep telling me that they have checked everything and it passed, but I have issue with explaining that, I try to play a game, which Barley do and As soon as the game starts it shuts down again.

This has been such a nightmare for me, I have bought computers for the last 25 years and My business computers are all DELL and are on for 12 hrs a day and they (4-2011's) never gave me a problem, I buy those for $800.

This LEMON MAC has cost me $3000 so far and it is only just about 2 years old.

Does anyone e;se have this problem???

 

[chedder’mac]

don’t have your issue but curious what cable, what game (and is it only when the game boots does this happen, or is it a constant across the board issue) are you booting up from an external drive? which OS is it? Sierra, HS or something else, are you running bootcamp and a windows game? more information would be helpful, plus what checks are the people at the Apple Store running?

 

[MacLemon91505]

don’t have your issue but curious what cable, what game (and is it only when the game boots does this happen, or is it a constant across the board issue) are you booting up from an external drive? which OS is it? Sierra, HS or something else, are you running bootcamp and a windows game? more information would be helpful, plus what checks are the people at the Apple Store running?

don’t have your issue but curious what cable, what game (and is it only when the game boots does this happen, or is it a constant across the board issue) are you booting up from an external drive? which OS is it? Sierra, HS or something else, are you running bootcamp and a windows game? more information would be helpful, plus what checks are the people at the Apple Store running?

The operating system is the latest one, We did a screen share with Apple and they had me download the latest version. which again shut the computer down while it was updating and this happened twice. I am at work right now, not in front of the Mac,to see the exact version.

The Game that I play, once in a while, maybe once or twice a year is "Call of Duty #4" and I noticed right from the beginning, when the computer was brand new out of the box, this computer used to freeze on this Game, and at the time I thought nothing of it, and now with a second visit and total reformat of the hard drive, plus a new power cable, literally day 3 when its back the 2nd time from the MAC store, it ***** down. The Power cable has to be unplugged for it to start again.
Apple Support Has called me and we even did a screen share, and it shut down while he was testing all the software and hardware on the Mac. We are not booting from an outside source. No windows game, nothing is run from outside.
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I don't have it.
Did you update its ram by yourself?
and did you update it?

Never touched this computer or upgraded the Ram.

 

[redheeler]

If the power cable has to be unplugged for it to start up again, I am 98% sure this is a power supply issue, not the logic board. The power supply will have to be replaced.

Next time, get AppleCare. Better to pay $150 upfront than $640 two years later if and when something fails from normal use. My 2015 5K iMac has coverage.

 

[bplein]

Do you use a UPS?

I had 2 UPSes in my "data closet" (my office is a bedroom and I have servers in the closet). The two UPSes would interact and sometimes flip my breaker. in addition they would affect my desktop that is on a different outlet but all on the same circuit. The breaker wouldn't flip, but my iMac would panic and power off. I would need to remove the power cord to restart it.

When I reduced the UPSes in my closet to a single UPS, my iMac became stable again.

Seems like the power supply on the iMac is seeing strange transients on the wire and trying to protect the system. And Apple cannot reproduce as they don't have the same electrical transients as you do at home. If you have a UPS on the same circuit, try it without the UPS for some time to see if it's the cause.