Hardware autospy. What killed this computer?

System:
AMD 3200+ 64 bit CPU
Asrock 939Dual
Enlight 450W PSU

This ancient thing was brought to me last week. The owner has already written it off and had a new a machine built but I still can't help but wonder what's wrong with this machine.

-Customer said the machine would take a few tries to get going when he would power it on in the morning.
-After a few months it would no longer power on.
-Brought it to me, fans would spin but nothing else. No beeps, nothing on the screen.
-Swapped PSUs. Machine now beeps 10 times = corrupted BIOS. Well crap.
-Got the BIOS reflashed with a floppy and the Ctrl + Home "trick".
-Machine boots, beeps, stuff on the screen. Everything seems healthy.
-Swap old PSU back in. Machine wouldn't boot. No beeps, nothing.
-Swap back to replacement PSU. Machines boots, but locks up after a few minutes.
-Restart. Machine powers on, runs fine for about two minutes, then powers off. After about 15 seconds, the machine powers back on (nothing on the screen), runs for a few seconds, and then powers off. This cycle repeats.

I tried: swapping RAM, PSU, video. I could try swapping the CPU but I don't think that's the issue. There are no leaking caps or burned circuits. Temps are fine... I scrubbed/lapped the heatsink and put some Arctic Silver on the chip.

This machine has proved itself to be completely unstable and is therefore headed for the recycle pile, it drives me nuts that I can't figure out what exactly is going wrong. If I could solder a new part onto the board and get it stable again it'd make a nice file server... much nicer than the typical Dell black-box Pentium 4 clogged with 8 tons of dust that I usually end up with after replacing a machine.

Has anyone ever seen behavior like this? I'm going to guess it's a bad voltage regulator.

I'd say that the PSU killed something you can't see... one of the VRM MOSFETs is a good bet.

Did you check the northbridge heatsink, clear the CMOS, all that usual stuff? And you're sure the replacement PSU is good?

Old Thrashbarg said:

I'd say that the PSU killed something you can't see... one of the VRM MOSFETs is a good bet.

Click to expand...

Agreed. When I was reading the OP the motherboard seemed to be the main issue because of the psu. Could be the psu "killed" it; at least in certain aspects.

A real shame if that 3200+ is fried because there is a demand in certain circles for skt 939 chips. eBay has a lot of 939 boards for sale but from what I have seen and read not as many cpus.

I've been running a 3200+ in what is now our second rig and in 5 years not even a hic-cup.