Need advice please - Bad Mobo or PSU?

loading5 · 30 May 2013 at 21:05

Ok so basically my PC will lose power randomly, doesn't matter what im doing, gaming, web etc. It will lose power, then it wont even turn on, sometime for minutes, sometimes for hours.

It is completely random, it happened first a couple of weeks back, wouldnt turn on for nearly a whole Sunday, since then its been fine, but today its playing up again.

When it wont turn on, i done some testing, I unplugged everything from the power supply, used the test button on my PSU, works fine, as soon as I connect the main motherboard lead however it trips it and loses power.

Its not my temps (they are fine) Windows is fine, my case is spotless inside, wiring is tidy, connectors seem ok, something is not right between my mobo and PSU. I even tried removing the mobo battery, that has mixed results in gaining power again however.

Here are my specs:

i7 3770k stock cooler, stock clock
Reference GTX680
Gigabyte Z77-D3H - F17 bios
16.0GB Dual-Channel DDR3 @ 666MHz (9-9-9-24)
112GB KINGSTON SV300S37A120G (SSD)
1863GB Seagate ST2000DM001-1CH164 (SATA)
PSU - Corsair AX860i

Please someone, this doesnt make sense, thanks in advance.

RJC · 30 May 2013 at 21:09

Hello and welcome to the forum

Can you list the make and model of your PSU.

Also check if possible your motherboard position in the case as you could be getting a short, also try running the system external to the case.

loading5 · 30 May 2013 at 21:17

Hello and thankyou

Ok I have edited my post, I have a Corsair AX860i PSU, so maybe the case is interfering with the motherboard? It seems positioned ok, I will have to try this the next time the computer loses power, at the moment its fine and im typing this on it!

RJC · 30 May 2013 at 21:26

You have decent PSU

Meant to also ask the case you are using?

loading5 · 30 May 2013 at 21:31

Doh should have posted that as well!!

Fractal R4 is my case, this problem just doest make sense to me, completely on its own the PSU will work fine (using the test button), as soon as the mobo is connected though it trips out.

If there was a short wouldn't it be constantly tripping? Why can I go days and hours without an issue, then some days I lose power for mins/hours.

RJC · 30 May 2013 at 21:46

Temperature & vibration could be a factor, but this is were we need to check different scenarios, running external to the case will rule out any possible shorts within the case.

If this works build the system bit by bit and run internal graphics just in case the GPU is coursing the short or even the hard drives.

Is there a possibility of testing your system with another psu.

cypto · 31 May 2013 at 03:24

If you have no spare psu lying around, you could always try jump starting (bridge the green and black wire on the 24 pin to simulate pressing the on button) with a fan connected and leave it running and check if it looses power or not after a few hours or so. That would rule out the power supply rather quickly. Then as RJC said part by part build back up you're system till you find what is shorting the system out.