TX650W V2 - Random shutdowns

Im having some problems with my newly purchased TX650 V2.

First time i mounted it, everything was running fine and it seemed to be working perfect. I left my PC running for about 30 minutes, and when i came back it was turned off - and i was unable to boot it up again. When pushing the switch NOTHING happened.

I then tried disconnecting everything and only attached the motherboard, and i was able to startup the PC. I try to plug things back on, one by one - but it seemed to be pretty random if it was able to start or not, no matter what i had connected.

I put in my old powersupply (which is only 500 watt, so that is not the issue).

And everything was working fine, i tried running the old power supply for a few days - no problems.

Then i plug back in the Corsair supply again and it seems to work fine again. I leave it in, thinking it might have been a one time problem. But after like 1½ days it happens again, the PC shuts off randomly and i am not able to power it up again.

Also in the time it was running i noticed a high pitch noice from the PSU, it sounds similar to the Coil whine, alot of other users mention on the forum. But not sure if this is the case.

I make a RMA to the place i purchased it, but today they just told me that they could NOT find any issues. They have been stress testing it for a couple of days, and tried everything - but they dident experience any issues at all.

They even said that they couldent hear the coil whine either (even tho is impossible to miss, when im using it).

So it might seem like something in my setup is causing the problems?

Any ideas what might be causing the problem?

And what can i try to investigate further?

Gigabyte GA-P55A-UD3

Intel Core i5-750

Corsair Dominator DHX+ DDR3 1600MHz 8GB

XFX Radeon HD 5850

Intel X25-M 80 GB (SSD)

Seagate Barracuda 7200.12 1 TB

Antec P190

Windows 7 (x64)

That is exactly what is happening to me, it's a brand new unit. :(:

I've noticed that when both of the 6pin cables are unplugged from the Gigabyte HD5850 OC video card, miraculously, the thing starts, monitor stays black, not enough power gets in the card obviously, when plugged back in, back to the same problem. RMA, the only solution?

Please follow the steps I gave to the O.P. and we can try and replace the unit.

Unbelievably, it was the brand new video card that was causing the problem.

Thanks anyway!