NEW PC turns off randomly. Can be 20 seconds into boot or when on desktop

[Oobie-]

Hey guys,

Issue: PC will turn itself off randomly, and I can only assume its the RAM/PSU/MOBO, as he hadn't even installed Windows to it when it started. He would be in the BIOS setting the time and date and it would turn off.
We took the RAM out and left one in and it still did it. Switched the RAM round and again same thing happened.

Now without having to waste valuable time with RMA'ing, does anyone have any idea why it could be doing this?

SPEC:
Intel Quad 6600
Abit IP-35E express
2gb corsair 800mhz 4-4-4-12
512mb XFX 8800gt alpha dog
500gb WD hdd
520W Corsair HX Series Modular PSU

Now, it has struck me that it could be BIOS related. But seeing as I'm not at his house, its kinda hard to go through BIOS settings and sort out what should be what.

-So any main points that need to be checked in the BIOS would be appreciated.

Thanks.

[staffsMike]

First thing I would check is the cpu temperature..it will turn its self off if there is a heat issue.

Failing that then build it outside the case to make sure there are no intermitent shorts.

The RAM should be at specific volts (on the label) which might cause problems if it isn't.

[Oobie-]

ah yes, thats what I omitted. He checked the CPU HSF and the Nbridge chipset, they were barely warm.

I'll get him on building it outside the case. Where should he want to place everything?

[Fraz]

Prob not the cause of your problem, but what voltage have you got that ram at? I'd imagine it should be 2.1v

[aidanjt]

It's most likely a hardware fault somewhere, things to rule out include:

PSU - Try shorting the 'on' pin and leave it running awhile to see if the same behaviour is observed.
CPU - Make sure it's properly seated, and that the HSF is mounted correctly, if it isn't it can cause overheating and the system will shut itself off, also, if there is a spare CPU available try that to rule out a faulty CPU.
Memory - make sure the module is firmly seated in the DIMM and the two latches click into place, also try sitting modules into other DIMMs, one may be soldered incorrectly. Also try a different module than that which came with the order.
Motherboard - try booting the other components on another motherboard if one is available to rule out other motherboard faults.

Of course while you're doing this, use the absolutely minimal required parts to boot the machine, motherboard, PSU, CPU, ram, and GPU to establish system stability, so you rule out other issues.

It's really a game of trial and error, keep going through combinations until you're able to reach a conclusion.

[staffsMike]

If you build outside the case then just put the mobo on some cardboard (the mobo box is useful i find) and then use the minimum components to boot.

[aidanjt]

I'll get him on building it outside the case. Where should he want to place everything?

Preferably on a solid & dry wooden surface, a plastic surface or piece of cardboard will surface also, as long as it's free of conductive materials it'll be fine.

[DanceswithUnix]

Is the CPU fan in the correct header? Some motherboards will shut down if they can't detect a spinning CPU fan.

Clutching at straws, but just a thought...

[peterb]

My first thought would be that the CPU cooler isn't mounted correctly and the CPU is overheating. It doesn't take very long to overheat without any effective cooling.

[aidanjt]

Yeah, especially given how fiddly those Intel push-down pins are. I wish they just used a rear bracket for HSF retention.

[Fraz]

PSU - Try shorting the 'on' pin and leave it running awhile to see if the same behaviour is observed.

Make sure that the PSU has at least a couple of fans attached (or some kind of load) if you do this.

[aidanjt]

Yes, good point to raise.

[s3ds]

1. is there an extra 6 pin power cable for the 8800gt ?
2. if you can get to the bios is the power down the 12v rail ok ?

i had a similar problem and when i traced it down the 12v line only gave 10.4v ( was a gf 7 and a socket A )
every thing else seems to be covered above

[Oobie-]

Well we've managed to try all the different slots with 1 module (slot 1 on the mobo is inaccessible due to the size of the hsf) and each time he booted the PC turned off within 20 secs of pushing the on switch.
He put the other module into slot 2, and has been running orthos for the past 2~ hours. The longest its been on for.

In regards to temperature. He says that when he touches the lowest part of the HSF, its warm - coretemp reports the temp at anything between 50 to 90 Degrees, and the BIOS reports it as 81 deg....

Somethings wrong, hes checking into it now.

[Fraz]

50 to 90 Degrees

[Oobie-]

1. is there an extra 6 pin power cable for the 8800gt ?
2. if you can get to the bios is the power down the 12v rail ok ?

i had a similar problem and when i traced it down the 12v line only gave 10.4v ( was a gf 7 and a socket A )
every thing else seems to be covered above

Missed your post s3ds - There is a 6 pin connector on the card and an 8 pin connector from the PSU, but 2 ping are detachable.

I'll get him to check the 12v rail in the BIOS