Random Power-offs

[wolfie138]

Any thoughts on the following?
my machine has been pretty solid since i built it, my first build. i did have some sudden shut-off issues a couple years ago right after build, and they seemed to be a know issue w/ the ASUS surge protection feature. took some advice, then all was good for well over a year.
then, i started getting power offs. usually it's only a matter of minutes after power-on, just total shut down and reboot to the option to start in safe mode etc, no BSODs. No events of note, simple a Kernel one saying the last shutdown was unexpected. the power-offs are totally random. i did things like run stress tests even though they usually happen when i'm doing nothing at all, or simple things like browsing, and the last thing i did was change the socket in my surge-protected multiblock, and all was fine for about a year. then, i got one again in Jan, then one in Mar. lately, i had one on the 10th. then 14th, then tonight - i powered the machine on, loaded a flash game on Kongregate then was in another room briefly and heard the music quit, and the thing had powered off.
the odd things is, aside from being random, it'll happen soon after reboot, then not happen again - i've been doing pretty heavy renders and stuff lately so i don't see that it's stress related. run HWInfo a few times, no temps seem out the ordinary or near break points.
build is:

Asus GeForce GTX 980 DirectCU II OC Strix 4096MB GDDR5 PCI-Express Graphics Card
Intel Core i7-4790K 4.00GHz (Devil's Canyon) Socket LGA1150 Processor
Kingston HyperX Savage Red 16GB
Asus Z97-A Intel Z97 (Socket 1150) DDR3 ATX Motherboard
Corsair RM Series RM 750 '80+ Gold' 750W Power Supply (CP-9020055-UK)
Crucial MX100 256GB SATA 2.5” 7mm SSD + 9.5mm Adapter (CT256MX100SSD1)
Cooler Master CM-690 III - USB 3.0 ATX Case - Seidon Promotion Free cooler Master Seidon
Noctua NH-U14S Ultra-Quiet Slim CPU Cooler with NF-A15 Fan
Seagate SSHD 7200RPM 3.5" 1TB SATA 6Gbs 64MB Cache - OEM (ST1000DX001) SSHD Hybrid Drive
Crucial MX100 128GB SATA 2.5” 7mm SSD + 9.5mm Adapter (CT128MX100SSD1)
WIndows 7 Home PRem.
TIA

 

[D.Roberts]

Have you got a spare PSU you could try it with?.

 

[Elfmeister.]

I've had some similar symptoms as to what you described, I somehow managed to get a 5p coin or screw drop into my case and wedge itself between the motherboard and casing, the other time I had to remove one of the four RAM modules which happened to be faulty, odd one that.

I would suggest, if you know how too, strip it all down, then either rebuild it outside the case, test with one RAM module, then build it back in the case and go from there.

In my experience of PSU's, they either work or they're dead

 

[new boy]

A friend of mine had a similar issue

He never got to the bottom of it, so in the end just ordered a new PC

To his surprise, the new PC was doing exactly the same thing!

It turned out to be a dodgy kettle lead

 

[wolfie138]

cheers guys. Don't have another PSU, but i was thinking of trying a new kettle lead first then going from there. like i said, the weird thing is that it's so random; if it was a dodgy PSu or Mobo, i'd expect issues a bit more regularly, and a lot more instability ~ i use my computer a lot, as in at least 3 hours a night and probably 8 a day at the weekend, and when that power-off manifests it does it once w/in about 5 or 10 mins of power-up, then nothing again. after i changed the connection to my multiblock and seemingly cured the issue last time, i was full sure it was more an issue external to the machine, so i was considering getting a UPS. i guess even if that doesn't cure the problem it might be worth the investment even though, paws crossed, i've only had two power cuts in about 8 years and wasn't on the machine either time.