Strange shutdown problem - psu?

FISHGUTS · 17 Aug 2006 at 12:06

Hope somebody can give me some advice.
When I turn my pc on, sometimes all the fans will start up on full speed but nothing else will happen, then if I turn it off and back on it will start up. After it has turned itself off I have to turn the psu off and on by the little switch on the back of it.
It will also completly shut down with no warning, just power down, no error messages, blue screens, nothing. This happens randomly, sometimes it will do it after 5 secs, 5 minutes, five hours or not at all.
I'm thinking it must be the psu even though it's only a few months old. I made a new rig out of old and new bits and it's been doing it since I made it.
Spec is abit at8, 3500 newcastle, x1800xt, 2 gb geil value, 150gb raptor,
580w hiper type r.
Anyone any ideas ?

FISHGUTS · 17 Aug 2006 at 16:53

bump

slap ed · 17 Aug 2006 at 17:04

r u sure the power cable is pushed firmly in the back off the psu ?

Trigger · 17 Aug 2006 at 17:40

FISHGUTS said:
bump

No need to bump your thread so early

slap_ed said:
r u sure the power cable is pushed firmly in the back off the psu ?

I doubt the machine would power up if the power cable wasn't in properly.

I would say it's one of two things- either the PSU is at fault because it sounds like the thermal cutout keeps kicking in or it's similar to the problem I had a while ago where a faulty BIOS to cause problems starting up and it wouldn't always output a video signal- a BIOS update fixed it

myriad · 17 Aug 2006 at 17:53

Ugh I had a similar problem to this it could be caused by anything I'm afraid. MY computer was cutting out and not posting properly and then only working after a few tries and pulling the power out for a while.

First thing to check is for latest BIOS version, I have had BIOS's that do not like cold booting before, this could be the cause of the boot problem, it is unlikely to be causing the crash problems, but then I have had BIOS versions that do strange things with the hard drives and will crash the machine.

Easiest thing to check, pull out a stick of RAM, I have recently had a stick of RAM that was causing crashes and stopping the PC from booting! Happens to every machine I try it with, fans spin up but no BIOS beeps and then the system hangs. If problem persists, try the other stick of RAM, if it still persists, then you are probably safe with the RAM, but finding another stick to test would confirm that.

Next, very scientifically you could pull out any extra hardware/cards in the system that could be causing the problem.

Next thing to look at is probably PSU, this is usually the no 1 cause of system instability, if you can get another one to try then it may help you diagnose, but if like me the problem is a bit random and you don't have a suitable psu then it can be hit and miss. I replaced my PSU and the problem persisted.

Lastly it could be your motherboard, if this is failing the cause could be here.

There's no easy answer to this problem, could be any one of a set of system components, if you do the above you will probably find the problem and spend the least amount on replacement hardware.