Is the PSU faulty, or could it be something else ?

[Chissler]

Hello guys! I am back to ask you guru's for more advice, and I hope it will be as helpfull as last time I had problems with my rig

I am currently experiencing a weird problem that I either atribute to the motherboard or the psu, but I am not really sure witch one are causing the problem. My computer will during high loads just shut down. By that I mean just go from normal, to off. It does no go through any shutdown procedure. It can be compared to what happens if a fuse blows in the braker box, only its just my computer that turns itself off.

So I have monitored the cpu and gpu temperatures, and they dont go abnormaly high, so I have already ruled out those two components. I have also run memchecker on the ram for about 1 day, and that didnt find anything.

My system is as following:
Intel Core 2 Quad Q6600 2.4GHz running at stock speed.
2 x Asus GeForce 8800GT 512MB GDDR3
Asus P5N-E SLI, nForce-650i SLI, ATX
Corsair TWIN2X 6400 DDR2, 4096MB CL5
Thermaltake Toughpower 850W, Modular.

So, do any of you guys have any idea on what is causing this ?

 

[jsc]

Possible the PSU. Try removing one video card to reduce the system load on the PSU.

(Yes, I know that the 850 watt capacity should be enough. )

 

[mi1ez]

I'd be tempted to go PSU too as it's under load that you're having issues, and temps are fine (although they would tend to slow rather than die)

 

[Chissler]

I am going to try and remove 1 of the gpu's. If this remove's the shutdowns I will say that the PSU is shot to pieces, and I will send it in for a new one. I still got waranty on it. It is also vital that I figure this out, since I am getting a new rig next month with 2x5850 running in crossfire on it.

 

[JasonAkkerman]

If you have a multimeter check the voltage between the +12v (Red or yellow, cant remember which right now) wire and the black wire next to it. You can use any available molex connectors, the large 4 wire ones that you connect to old hard drives and CD ROMs. Check them all. Check them while the PC is running.

IF YOU ARE NOT COMFORTABLE WITH THESE ACTIONS DON'T DO IT. Poking around with metal pins while the PC is running can be dangerous for the PC. You shouldn't have any problems if you stick to just the molex connectors and don't bridge the yellow and red wires together.

Depending on your PSU you will have a given number of +12v rails. A rail is a separate +12v source. It is possible that you have the majority of devices in your PC connected to the same rail, causing a voltage drop, and the shutdown.

I ran into this problem once before after taking everything apart for a cleaning. Everything worked fine beforehand, but when I put everything back together I had similar problems.

If you find that any +12 wire is off my more then 10% (lower then 10.8v, personally I would keep it above 11) there is a good chance that is your problem, or just a problem in general with the PSU. Try moving some connections around and see if you have the same problems.

 

[rodney_ws]

I think you're on the right track with the PSU. Even if the PSU still misbehaves on a lighter load, it COULD still be the source of your problem. For your sake I hope the reduced load clears up your problem so you can conclusively point at the PSU. If the problem persists, well... you won't have a definitive answer, but I'd still be suspicious of your PSU. This is where friends with spare rigs/parts come in handy.

 

[pcworm]

might be a dying capacitor on your mobo,esp if it is normal (not solid state) capacitor take the board out, chech the capacitors around the cpu, if any of them are inflated, vola..
even if you are out on the mobo waranty, you can solder the diffective capacitor yourself!

 

[rodney_ws]

Ahh... forgot about puffed capacitors. PCWorm really might be on to something with his suggestion. The tops of the capacitors on your motherboard should be concave (meaning they sink down) ... if they're convex (puffed upward from the capacitor) then that is likely your problem. If there is some leakage out of the top of the capacitor, well you really have a problem.

 

[shovenose]

Ahh... forgot about puffed capacitors. PCWorm really might be on to something with his suggestion. The tops of the capacitors on your motherboard should be concave (meaning they sink down) ... if they're convex (puffed upward from the capacitor) then that is likely your problem. If there is some leakage out of the top of the capacitor, well you really have a problem.

flat is ok too