No lights, nothing, but high-pitched tone when unplugged

[Barns]

Hi,

One of the PCs in my office stopped working the other day and now does absolutely nothing when you press the on switch, no lights, no noises, absolutely nothing. However, when you unplug the cable from the back it makes a faint high-pitched noise which gradually dies away.

I've replaced the power pack with one I know is good, reseated the RAM etc but it still doesn't even POST.

Any ideas?

Thanks in advance.

 

[Twoboxer]

If you used a known good psu, and the squeal remains, the likely source of the problem shifts to a bad motherboard.

The specific configuration, make/model of the two PSUs, etc would be helpful info.

 

[Barns]

The motherboard is an ASRock G31M-VS and the PSU in there at the moment is an LPJ12-450W. The other PSU it had before which is now working fine in another PC is a P4-450W.

It's not really a squeal, it's a very high-pitched, faint tone which lowers in pitch and disappears over a few seconds. It just seems strange to me that even the power light on the switch doesn't come on. If it was bad RAM or something it would still at least have lights, no?

Thanks for trying to help Twoboxer.

 

[Twoboxer]

Checking Newegg, 500W Linkworld PSUs selling for $22 is a strong indication of low quality.

If a PSU that works in one mobo won't light the lights of another, that mobo is bad.

I'd be guessing that your PSU isn't delivering clean power, and eventually burned out the regulating circuits on the motherboard.

I'd strongly recommend not powering your office PCs with anything but quality PSUs. They can prove to be destructive.

 

[Barns]

I inherited the PCs in the office/Internet cafe when I took over the place, an ecolodge resort in rural Laos, and getting anything of quality here is somewhat tricky, especially technological stuff! They're only for guest Internet use etc so they don't need to exactly be top notch!

So a fried motherboard would mean no lights or anything yes? If so, I'll pick another one up next time I'm in town, they're not that expensive here but that's probably because they're cheap stuff imported from China...

Thanks again mate.

 

[mosox]

Standard troubleshooting procedure
http://www.tomshardware.co.uk/forum/261145-13-perform-steps-posting-boot-video-problems

 

[Twoboxer]

Again, a known working psu that won't power another mobo (especially in a system that *was* working) shifts the odds dramatically to "mobo problem". Theoretically, it is possible it could be something else, but its not very likely.

Sorry for your difficulties - and the working environment - but I'd encourage you to do your best to ensure you're using a psu of minimum quality. If you get a cheap mobo and it fails prematurely, the odds are good it won't kill anything else.

Not so with a psu.