Problem with power? What do do next?

[Brant]

For the past week or so, my system had been behaving rather strangely. I've been having random reboots which I originally thought was due to overheating -- I'm still using the OEM HSF that came with my barton 2500+, and my case has always been fairly hot to begin with even with a few extra fans. I bought some arctic silver 5 and slapped it on, and my CPU temp dropped a fair bit, but the restarts persisted.

Eventually though, the problem got worse. The PC would reset every 5-10 minutes, but soon it was doing it every 30 seconds. So, I opened it up and took another look inside.

What I found gave me a shock... several pins on the ATX connector were scorched, the plastic melted. If I had my digital camera, I'd post some pics, but I don't think it would be too hard to imagine. The interesting thing was WHICH pins were fried... just the red ones, the +5V pins. Every one of them was scorched black and the plastic melted, while the rest were perfectly OK. (The melted plastic made unplugging the thing a rather interesting challenge, but that's another story)

Here's a list of everything in the box I can think of:
PSU: Thermaltake Purepower 420W (model #: HPC-420-102 DF)
CPU: Barton 2500+ (OEM heat sink/fan, not overclocked)
Motherboard: Asus A7N8X
2x OCZ PC3200 256MB
Radeon 9800 (non-pro, not overclocked)
SB Live! Value (first generation, not a 5.1)
2x 120mm case fans (one in the front of the case, one in the back)
LG 32x CD-RW
7200rpm 120GB Seagate Barracuda
7200rpm 100GB WD Caviar
5400rpm 40GB Maxtor

I pulled everything out of the system except for a stick of ram, the radeon,and the cpu, then tried booting the system. After letting it sit in the bios for a few minutes, I noticed the ATX connector was starting to get warm. So, I guess the problem lies somewhere in one of those four components.My problem is, I don't know what to do next. The motherboard isn't dead, at least I don't think so, as the system was powered up and working fine
(although rebooting every 10 seconds).

This isn't the first PSU this system has had. About six months ago when I put the motherboard + cpu + radeon into it, my original power supply (some generic 300W deal) died, which prompted the purchase of the thermaltake. I also don't quite understand why only the +5V pins were fried; if the PSU was at fault wouldn't the whole thing gone up in smoke? Unfortunately I don't have an old PSU on hand that I can use to test with... Is there anything I can do to figure out where the problem lies that won't result in more damage?

Any advice or insights would be greatly appreciated. I'd really like to avoid buying a new motherboard if I could, but I simply don't know what my options are right now. I don't even know what's causing this.

 

[Sarge]

I would try taking the motherboard out of the case and and try running it outside the case. Maybe there is something behind the mobo (like a standoff out of place or a loose screw) shorting things out. A loose screw could have been there for a long time causing no problems, then been dislodged by moving the computer around and is now causing a short.
Just WAG, hope it is some help.

 

[Brant]

Thanks for the tip. I pulled the motherboard out of the case and ran it for a while, but I still don't really have a good way to diagnose the problem... I ran the system for a few minutes and the atx connector seemed to get a little bit warm where the red wires are, but I don't know if that's normal or if I still have a short somewhere. (The temperature difference was barely noticable, and I don't know if leaving the system on for any extended duration is a good idea when there might be a short circuit somewhere)

 

[Novensu]

The first thing I would do is to buy a good case <Antec> with a rock solid power supply. I learned my lesson the hard way many years ago. I can't remember all of the components I have burned up, until I wised up and started buying good cases and power supplies.


~N

 

[Gruntled Employee]

it sounds like an amp draw is overheating the psu, make sure the radeon has it's own channel so it doesn't have to share power with anything....your psu may be damaged already.