Win XP PC turning itself off

[benjir]

My computer (AMD 64 bit 3500+) keeps turning itself off randomly. I've narrowed the issue down somewhat but need help to get any further...

The only time it doesn't turn itself off is when it's sitting in the BIOS (Award).
BIOS shows CPU temp is about 54 deg celcius, and all fans are working.
I've blown out all dust and tried swapping ram sticks to no avail.

12 volt supply is sitting on about 11.8 V, not sure if this is an issue?

Also when it turns itself off, the keyboard lights stay on (Numlock, etc), but all fans and drives turn off.

 

[Archean]

Voltage seems to be within range i.e. +/- 5% on 12V rail.

How old is this PSU by the way? Its make/model etc.

Please give complete specs of this system, and your post give the impression that underload (i.e. when its booted with an OS/being used etc.) it is working perfectly fine?

Also, have you checked for updated BIOS for your motherboard ? May be it is some issue with this particular release of BIOS. Regards

 

[benjir]

system specs

PS is Gigatec ATX 450 (Nov 2006)
450W

1 GB (2 x 500 MB) DDR 400 Ram sticks

160 & 80 GB HDDs (IDE)

NVidia Video card 256 MB

WinFast Motherboard

Unfortunately I'm not sure how to obtain the model numbers anymore, as I tried reinstalling windows XP, and am now unable to finish installation due to power cutout issues.

Previously tried repairing the install, thought it had fixed the issue, then after about 12 hours the comp switched off

Computer was in transit for 2 months, was working fine before transit, now has this issue since i got it 2 weeks ago...

Cheers,
Ben

 

[Archean]

Please ensure that all connectors (data cables/power connectors etc.) are properly seated. Also, I am unsure about quality of these gigatech PSUs.

Anyway, try booting with minimum required hardware, i.e. one memory stick, one hdd etc. and see what happens, if system boots normally, probability is you need a new PSU.

 

[techsuitor]

Remove your ram and video card, then try to turn it on. Make sure that the cables/connectors are properly seated.

 

[benjir]

No good with minimum hardware (1 HDD, 1 RAM stick), seems to turn off even faster now. Still works great when viewing or altering the BIOS settings but as soon as i try to continue the OS install, it dies.
Will try unplugging and re-plugging everything tomorrow if i get a chance, to make sure the seating is good.
Thanks

In regards to removing RAM & Video card, after i switch it on, the computer makes a long beep every 5 seconds or so and the screen stays blank.. Does this mean anything?

 

[mike1959]

PC switching off.

This sounds like a PSU starting to fail. But take apart everything you can, even the CPU from the socket, and re-build. It's free and you might find the fault. I moved a PC to a different house on the back seat of a car, packed very carefully with coats each side. Set up at the other end, and power supply failed straight away ! A clue to your PC is it's ok while on BIOS screen, but when drawing more current, it trips out. Would be interested to know what the result is to this. Good luck.

 

[SBHack]

Have you checked outlet for dirty power? Having steady voltage in the correct range is as important as anything else.

 

[techsuitor]

What happens next after you inserted again the RAM/Video card?

@ SBHack -- Yeah! .. such fluctuation of voltage is a big issue.