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xinix
November 13th, 2007, 10:00 PM
I think I may have confirmed this in IRC but there was so much other chatter going on that responses would fly off screen before I could read them. But, i think my CPU is fried and wanted to confirm this diagnosis.
I came home on Sunday to find my rig was off. When I hit the power buttons the fans would come on for a second and then shutoff. I stripped the system down to the basics, CPU, mem and vid. Same results. If I take the CPU out and power it on the fans run until I kill the power either by unplugging or holding the power button. I get the same results if I simply disconnect the CPU power supply (square 4 pin plug). It doesn't post at all. The mobo manual doesn't list any beep code for missing/dead CPU, but I figure this is a component that the mobo needs in order to get as far as beeping errors. Any thoughts?

Edit:
Tested with a working PSU and had the same results.

Dixon Bainbridge
November 13th, 2007, 10:06 PM
Look on the underside of the CPU. If its brown, its fried :)

xinix
November 13th, 2007, 10:15 PM
It looks fine.

ddrichardson
November 13th, 2007, 11:16 PM
It doesn't need to have been something as catastrophic as a burn out. Static damage to integrated circuits can often not affect systems until later in their life span.

Have you looked at the motherboard support site? There's usually some good post mortem advice.

I'm no expert with i386 hardware but as far as I know the CPU is required for all but the most fundamental built in test functions.

xinix
November 13th, 2007, 11:44 PM
I've tried the motherboards support advice from the knowledge base question that describes my symptoms. Basically it says to reset the CMOS but I've tried this and it doesn't work.

ddrichardson
November 13th, 2007, 11:48 PM
Reset the CMOS is the hardware support equivalent of an ISP telling you to restart Windows.

koleoptero
November 14th, 2007, 01:43 AM
I've had the same problem and it was the power supply. Try a different one from aanother pc and see if it works.

jflaker
November 14th, 2007, 01:52 AM
I think I may have confirmed this in IRC but there was so much other chatter going on that responses would fly off screen before I could read them. But, i think my CPU is fried and wanted to confirm this diagnosis.
I came home on Sunday to find my rig was off. When I hit the power buttons the fans would come on for a second and then shutoff. I stripped the system down to the basics, CPU, mem and vid. Same results. If I take the CPU out and power it on the fans run until I kill the power either by unplugging or holding the power button. I get the same results if I simply disconnect the CPU power supply (square 4 pin plug). It doesn't post at all. The mobo manual doesn't list any beep code for missing/dead cpu, but I figure this is a component that the mobo needs in order to get as far as beeping errors. Any thoughts?

I am suspecting a powersupply rather than the system board

the PSU will commit suicide in favor of saving all other electronics. It is basically an expendable part. Since you are saying it comes on momentarily then shuts off, almost certain it is the PSU

(almost 19 years IT)

-grubby
November 14th, 2007, 01:56 AM
I am suspecting a powersupply rather than the system board

the PSU will commit suicide in favor of saving all other electronics. It is basically an expendable part. Since you are saying it comes on momentarily then shuts off, almost certain it is the PSU

(almost 19 years IT)

so you're saying the PSU cares about the other hardware components and sacrifices itself in favor of saving the other hardware components?what a hero

jflaker
November 14th, 2007, 01:57 AM
so you're saying the PSU cares about the other hardware components and sacrifices itself?what a hero

It is a selfless PSU!

nutz
November 14th, 2007, 01:59 AM
Sounds like your PSU took a crap. CPUs don't just die like that and these days they all cope with overheating pretty well. Sounds to me like your PSU took a crap or you have a bad capacitor on your mainboard.

ddrichardson
November 14th, 2007, 02:12 PM
Sorry, I'm not sure why people are suggesting the PSU - the OP said it functions when CPU is disconnected, voltage regulation is carried out by the PSU and as for sacrificing itself - only insofar as there are fuses in good PSUs and cheap toroidal transformers in cheap ones that burn out.

But I could be wrong and PSU are cheaper so why not try it first.

rustybronco
November 14th, 2007, 02:16 PM
psu...

xinix
November 14th, 2007, 04:43 PM
I just tested with a working PSU (the one from this computer) and I got the same results. If it were the mobo, wouldn't it short out without the CPU too?

ddrichardson
November 14th, 2007, 08:28 PM
Do you mean is it a problem with the motherboard?

xinix
November 14th, 2007, 09:47 PM
Yes, could the problem be a faulty motherboard? Removing the CPU (or CPU power plug) results in the fans staying on, but does this necessarily mean that it's the cause of the problem? If it is the motherboard shorting out, would removing the CPU stop this from happening or would the board continue to fail without this component? Replacing the CPU won't upset me too much since I've been considering upgrading it to the best option i can plug into a 939 socket. On the other hand, I'm not too keen on any of the motherboards I've found with 939 sockets.

ddrichardson
November 14th, 2007, 10:23 PM
When you say the CPU power plug are you referring to the motherboard power connector or the CPU cooling fan connector?

xinix
November 14th, 2007, 10:26 PM
The square 4 pin connector. Not the fan or the 20 pin connector.

ddrichardson
November 14th, 2007, 10:45 PM
Generally I'd swap out the mainboard before the processor. If you can get hold of a known working one to test with, otherwise its down to making an educated guess, my gut feeling with your symptoms is the processor.

Zero Prime
November 14th, 2007, 11:59 PM
Dude, you have the same exact problem I had. I had to replace my motherboard and everything worked fine after that. I replaced my power supply as well and I would recommend doing the same if you have an old OEM PSU.

xinix
November 20th, 2007, 05:53 PM
Dude, you have the same exact problem I had. I had to replace my motherboard and everything worked fine after that. I replaced my power supply as well and I would recommend doing the same if you have an old OEM PSU.

Yep that would seem to be the problem. I'm still waiting on a new board but after taking out the old one I spotted a vented capacitor. I had looked for this while the board was in the case but this one was hidden by cables and such.

ddrichardson
November 20th, 2007, 07:50 PM
Replace the capacitor, it'll say on it what value it is.

xinix
November 20th, 2007, 09:10 PM
Unfortunately, replacing the capacitor is out of my area of expertise. Is this worth sending off to a shop to do?

aimran
November 20th, 2007, 09:24 PM
Don't they teach kids nowadays to solder :|

:lolflag:

Lostincyberspace
November 20th, 2007, 09:34 PM
hey no will teach. they say just get a new one its less hassle.

xinix
November 20th, 2007, 10:09 PM
Heh, I was taught how to solder, only it was for metal smithing and not electronics. Something tells me that the tools I have aren't the right ones for this job. :twisted:

ddrichardson
November 21st, 2007, 10:41 AM
You can pick up a kit from radio shack or whatever, even in the UK they're only around £10, capacitors are cheap as chips - all you need is a de-solderer and an iron. Heat the current solder and suck it off then fit the new capacitor, flay the pins out a little and then solder it back in. Just make sure you don't apply to much heat or you'll lift the tracks off the PCB. A little letoxane to clean off any flux and you'll have spent around £15 rather than at least three times that on a new motherboard - if it's borked anyway then what have you got to lose?