Troubleshooting Suggestions?

[joe_cool]

BACKGROUND
Homebuilt computer. ASUS P4P800 Deluxe, Intel P4 2.48Ghz, 512MB Ram, PowerSupply 450W, CD, DVDburner, 2 HDD in RAID, one HDD IDE, ATI xxxx with tuner.

Paid close attention to temps while I replaced the 5 case fans (closeout sale case) with a 120mm fan. Worked hard with free CPU cycles going to BOINC.

Worked reliably for 2 years, about 3 times a year it would have a random reset.

SITUATION
Computer went dark - pressed reset button no help.

Suspected power supply. Replaced power supply
Does not power up

Suspected CPU. Replaced CPU
Does not power up

Suspected mobo. Read a troubleshooting chart. Mobo LED light is on, I have power. Removed mobo from case and reassembled on table. Shorted the PWRSW pins and the computer lives. Boots into windows and I can login and runn apps. There is joy in Muddville!
Checked power switch, it works. Rebooted again and it works! Time to reassemble

While I was working on the case (totally seperate from the computer at this time) for about 20 minutes, I glanced over and noticed that both the graphics board fan and the cpu fan had stopped. I had not touched the computer or had been typing/interacting with it at all.

Surveyed the components. HDD's were cool/warm. The videocard was warm, the northbridge was warm, the CPU was hot. Suspected temperatures as cause. Let cool down. Rebooted to BIOS and found that I had set the fan voltage at 11/16 of maximum (to minimize noise). Set the value back to 16/16 and saved setting. Rebooted. Went dark again. Went to bed.

Rebooted computer. Used ASUS probe to monitor CPU temp. CPU temp ramped up to 36C during startup, then cooled down to 32C after login and I let it idle. After a couple of minutes at 32C it shutdown.

Suggestions?

[Cricket]

Check the southbridge for dark spots. That motherboard is known to have issues with front USB ports being hot-plugged and frying the southbridge.

Cricket

[joe_cool]

Thanks for the reply.

The southbridge looks normal, no spots or discolorations.


What else might it be?

[Cricket]

No loose or stray standoffs in the motherboard mounting tray?

What brand power supply are you using now? What brand was the original?

Cricket

[joe_cool]

PS was a "Turbolink" and it is a "Cooler Master" now.

The motherboard is now on a wood table, nothing underneath it (standoffs etc).


Thanks for the quick reply.

[Cricket]

Originally Posted by joe_cool PS was a "Turbolink"

That's a rubbish power supply. Good thing you replaced it.

Originally Posted by joe_cool and it is a "Cooler Master" now.

Uh...that one is a little better, but there are many others that are superior to it.

Cricket