Project Reality Forums

So six months ago I moved house 260 miles and my PC survives just fine. Last week I moved house 2 miles, and disaster strikes.

Popped my rig into the study today and wired everything up. Flick the switch, there's a high-pitched whining noise, the smell of something burnt and nothing happens, not even an error beep. Quick sniff of the PSU confirms its burnt out.

Minor panic - I start night shifts tomorrow, I need the pc for entertainment tonight as I put body clock back! Dash out, buy a decent new psu... spend an hour inside the case... flick the switch, and vroooom! All fans on full whack, nothing on screen, no POST. Bugger.

Pull out all expansion cards, no better. Power switch on the front won't turn off or reset the pc. Try a different GPU in case it's a display problem. No joy.

In the past when a psu has blew on me, it took the mobo too - but then, the machine wouldn't even switch on with a new power unit inside, let alone spin up HDDs, fans and the CPU.

So, question is - anyone aware if its possible for a power spike/surge to kill some functionality of a mobo but not all? If so, that's probably what's happened. If not, what am I missing here - it's been years since I last had to troubleshoot a non-POSTing pc, so Im wondering if I'm overlooking summat!

A corrupted BIOS chip? You can try "conning" the BIOS into activating its recovery mode.

If you have or can find the CMOS specific jumper, "short" it to clear and reset the CMOS memory. Boot up. You should be able to get into the BIOS now. (Don't forget to put the jumper back to its previous position after powering back down). Your hardware is programmed to act one way when the jumper is shorted, and another way when it is left open.

If you can't be bothered by all this and you have time, pop your CMOS battery out, leave it out overnight to clear the memory. Then pop it back in.

That's my quick answer. I can look into it more tomorrow via lucidity of daylight.

Is it possible that the smell did not originate from the PSU but rather from a component inside, then got vented out throught he CPU...
Meaning: you might still have an intact PSU and you mobo fried.
Also, afaik the whining noise originated from an oscillatory circuit being smoked. Possibly a capacitor that busted (maybe on the mobo?). Check for visual indications: bloating, rusting, leaking.
"Power switch on the front won't turn off or reset the pc" is to me a pretty good hint that the mobo is to be looked at.

Furthermore, I am not sure if a power burst will partially damage a mobo leaving it half-way operational but I definitly had a few mobos which would behave this way (usually after overheating).

Check for cables and double check that there are no debris or sorts causing a short.

Psu definitely went as well - new psu will power the fans, HDDs etc whilst the old one wouldn't.
Pulled the battery and tried a cmos clear but doesn't seem to have helped. No visual signs of damage nor shorts and I've reconnected every lead, cable and card to see if it's a loose connection. Looks like a dodgy mobo indeed.

ta guys.

Yep seems like it. My next guess would have to be that the memory controller chip may have fried. It's very vulnerable to static discharges and power surges. It's at or near the tiny orange or red pilot-light sitting beside the ram slots. If it's not on then the chips fried.

Whatever had died on it, it was definitely the mobo. Put a P45-based board in on Saturday and it booted first time - straight into Windows which detected the new chipset, sorted itself out, asked for a reboot and then loaded perfectly... didn't even ask for the DVD to install new drivers from. Somewhat impressed with W7!

and they lived happily ever after

Happy to see you solved the problem.

[R-DEV]Masaq wrote:Whatever had died on it, it was definitely the mobo. Put a P45-based board in on Saturday and it booted first time - straight into Windows which detected the new chipset, sorted itself out, asked for a reboot and then loaded perfectly... didn't even ask for the DVD to install new drivers from. Somewhat impressed with W7!

Good isn't it?
PSU's can blow mobos often when they fail. Quite common after transit too.
The missus' machine had the same happen there a while back.
Really good idea to have your machine 100% cool down if used heavily before you move it. good advice for LAN parties.
W7 of course will have a different response if you change your CPU and mobo together, but I'm sure most people are aware of that.