What's My Problem?

[GreenGrinch]

So here's what happen, my computer work just fine when I left for shower. When I came back, my computer was off and I smell something burned. A quick look inside the computer doesn't show anything obvious. I tried to turn it back on, of course it didn't do anything. So I thought, ok, I probably blow my PS (Antec 480W).
So I replaced the PS with my old PS (Antec 300W), this time I'm only connecting the motherboard (Epox 8RDA3+), video card fan (Radeon 9500 Pro), my main hard drive and 2 case fan (12cm & 9cm). When I tried to plug in power cable to the back of the PS, fire & smoke came out from PS again. So I'm left with 2 dead PS. So I'm thinking, maybe it's not the PS that's causing the problem.

Here's where I hope you guys can shed me some light. I'm going to run out and buy another power supply (probably Antec 550W), but I'm really afraid having 3 dead PS. What would be the best way for me to diagnose the problem? I'm thinking maybe there's a short circuit that's causing the PS to overload. I think the suspects are the motherboard, CPU (AMD Barton 2400), video card, HD (unlikely, new 300GB Seagate SATA), or the 2 case fan. Would a failure in any of these hardware causes a short circuit?
I didn't see any burn mark in any of those component, although I haven't removed the CPU heatsink to look at the CPU. Thank you guys!

 

[furballi]

Personally, I'd strip the MB bare and retest outside the case. If the PSU smokes, then you've isolated the problem to the MB. I doubt that the CPU or RAM could blow the PSU.

 

[letdown427]

When I tried to plug in power cable to the back of the PS, fire & smoke came out from PS again.

As in, when you first plugged it in? Wouldn't that imply there's a short in the power cable or something? I'd say use a different one just to be safe. Just a thought.

 

[GreenGrinch]

Thanks guys. Yeah, the PS smoked as in when I plugged the power cable to the back of the PS. I will replace that just to be safe. And if that solves it, great, if not, I'll try furballi's suggestion. Thanks again!

 

[Jiggz]

It'll be a very expensive troubleshooting but you can try something different first instead of sacrificing another PSU. Dismount the mobo and PSU from the case. Place them on an insulated mat or card board. Do not install anything from the mobo (no cpu, no video card, nothing). Now power up. You're not suppose to see anything including smoke! If there's no smoke or smell, now you can move on by installing the CPU. Continue powering up and down while the whole thing is off the case until you get to the point where you have a video card and monitor connected. If the system still do not indicate any burning, now re-install it back to the case. Be careful make sure nothing in the mobo gets shorted to the case. Anytime during the troubleshooting, you smell or see smoke, the last item you re-installed is the culprit. It'll be great if you troubleshoot this using a not so expensive psu. Using a brand new 500W is just way too expensive. Check the For Sale/Trade forum.

 

[GreenGrinch]

Ok, I got several old PSU and tested all of the components. I didn't connect all the components at once since the old PSU wouldn't be able to handle it, it's always the bare (Mobo, CPU, RAM & VGA) plus some other component. Everything looks ok, I don't get blown PSU or anything, so what the heck was blowing my 2 PSU?? One thing I noticed though is that the fan for my video card is not working anymore, could that be cause? Normally, won't the video come out at all if the video fan not running?

 

[furballi]

Could be a short to the case. You will still get video. However, you can fry the video chip if the fan is not running.

 

[GreenGrinch]

That's what I was thinking too, but while testing, I left the mobo inside the case. I used the same PSU cable that might be causing a short. Or maybe it's just 2 unrelated incident that blown up the PSU.

 

[d3lt4]

Maybe the first PSU blew and then when yu plugged in the next one the mobo was still not discharged and then blew your newer PSU. i would suggest discharging your mobo first via something metal connected to your mobo and something else metal.
just a thought.