Ive fried something but im not sure what! Please Help!!

Doc Shorla · 2 Dec 2007 at 20:29

Was on my comp today, suddenly shut down and smelt a burning smell...not good. Tried to restart and no joy. Took everything out the case and start it with just the mobo, cpu and psu. When i switch the psu on the light comes on fine, then the asus light comes on the mobo so power is getting to the board. When i switch it on the cpu fan spins for literally a split second then switches itself off. although the asus light stays on. Its as if its shorting on something but its not. Had a look around the board and chip and cant see anything out of the ordinary. Does anyone have any ideas what it could be, dont have any other bits to test seperate componants on. Thanks.

Rroff · 2 Dec 2007 at 20:37

What parts do you have in your system? graphics card make and model and so on...

PowerDemon · 2 Dec 2007 at 20:44

Its likely to be the PSU.

Doc Shorla · 2 Dec 2007 at 21:11

Parts-Asus P5B, E6600, ATI 1950xt, Psu is Silverstone 600w (or something around there). Do you think its the psu? it appears to be working as i have a phase case which ive plugged it into and runs that fine.

Corasik · 2 Dec 2007 at 22:47

Remeber the PSU has several independant rails, 3.3V 5V 12V... Its quite possible that for example the 3.3V rail could be fried (3.3 powers Ram and several other systems), yet the 12V regulators could still be working (perhaps your phase uses 12v only).

As you can power up the PSU with your Phase case.. get a multimeter, and check the voltages are all good on all rails. Although even this isnt a 'perfect' test as your putting no load on it. It could be that there is a fault causing ripple, or other 'noise' on the power rails, and that is quite harmfull for the motherboard.

A faulty PSU could damage the motherboard, so its best to test it first. Of course its possible the motherboard has failed, if you smelt burning you may be able to see physical damage on the board. My bet is the PSU though.

Doc Shorla · 2 Dec 2007 at 23:10

I think my silverstone is a single rail jobbie, will the above still apply? So its looking like psu?

Corasik · 2 Dec 2007 at 23:15

When silverstone say its Single rail, they mean single 12V rail, rather than 2-4 separate 12V rails.

However the 5V, 3.3V 5Vstandby, and -12v rails are still 'independant' and any one could have failed, although -12 isnt highly used anymore, and -5 has been almost totally dropped (Seasonics dont even have a -5v rail anymore).

So yes, you still need to test all its voltage outputs to be sure.

Im not saying 100% its the PSU, its very possible that the voltage regulators on the motherboard which convert 12V down to 1v-1.5V for the CPU have fried.. But as you can power the PSU its probably the easiest to test

Doc Shorla · 2 Dec 2007 at 23:19

Thanks Corasik, good explination, will give that a try

EffBee · 3 Dec 2007 at 09:47

Don't disregard power supply.

I had a problem like yours a few years ago. A slight smell of burning which I couldn't nail down. Things kept running tho' but for the next few weeks had increasing problems like boot failures, graphics artifacts, spontaneous reboots, system instability and so on.

I eliminated the PSU as a cause of trouble because it was (for the time) a high wattage expensive Enermax unit just out of warranty. I had few spares so bought new graphic card. Didn't fix it. New Mobo, processor, memory. Didn't fix it. In desperation bought a cheap PSU from a place with people in purple shirts. Problem solved. Still using that power supply now as it happens.

Bit miffed since I'd already thrown the old kit away and so couldn't test it to see if it still worked or whether the PSU had damaged them too.

Still - got some upgrades out of it.

londonbairn · 3 Dec 2007 at 09:58

Probably PSU as they have said. A Hiper I had a while back had an awful burning smell. Luckily I switched the PC off rapidly before it blew up...it did however make 2 of my Hard drives very unreliable (which were RMA'd anyhow)