Computer won't startup

[Davedc]

I've built about 8 computers in the past 5 years, so I do have a little experience. The one I put together this morning won't start. The motherboard, case and power supply are the only componants that are from a computer I was already using. I put in a new P4 cpu, new ram, new floppy, cd-rw and hdd, new cables and video card. The first time I pushed the power button, I got a heavy smell of electrical burning but saw no smoke. The power button won't turn off the power (the fans and drives still spin and light up) even after holding in for 10 seconds. The power button will turn it on. Nothing shows on the monitor, no bios info or anything. I unplugged the drives and took out the ram, still no change. I changed video cards, still the same. I figure it has to be the processor or the Mainboard thats fried...but I'm not too bright and could be wrong. Any ideas???
TIA
Dave

[theopetro]

remove the heatsink from the cpu and clean the paste off with 91% isopropal (rubbing) alcohol if the cpu is fried there will be a burn mark on the cpu and heatsink

[bailey]

Originally Posted by theopetro remove the heatsink from the cpu and clean the paste off with 91% isopropal (rubbing) alcohol if the cpu is fried there will be a burn mark on the cpu and heatsink

p4's cannot over heat at all, so its just not possible.
look elswere. its a well known fact that when you let the smoke out, it won't work, so something got fried,
are you sure the psu is p4 ready ?

[Davedc]

No question it's P4 ready, I had it running a 2.4 ghz P4 for at least 6 months I guess. The new CPU is a slower P4. I'm leaning toward the motherboard since the pwr supply still gives juice to the fans. Would the motherboard going bad account for the fact that the pwr supply won't shut off even after holding in the pwr button for 6 secs...or more.
Dave

[JAYMAN]

I have seen this before. But the issue was that the 12v CPU connector was not plugged in! Not sure if that is your issue, but all professionals make stupid mistakes sometimes (/cough - ask me how I know this!! - haha)

[Davedc]

I'm no pro but I did make sure things were plugged in. I took EVERYTHING apart now, the 20 pin ATX plug to the mobo smelled the strongest of that elecrical burn. Now that I have the mobo out, I looked at it with a magnifying glass and found something that actually looks burned, right next to that plug. The board is a Gigabyte Titan GA-8S648FX-L. The little chip thing thats burned is on the left.

[Cricket]

Sounds like a resistor melted. Time to replace the motherboard.

Cricket

[Davedc]

Not sure if its a resistor or what it is, but what concerns me is what caused it to burn up. I just ordered a new mobo and I hope when I put it together with all the same componants that it doesn't melt down too.
dave

[ltmccaul]

It could also be a problem with the power button on the case. On those very rare occasions, behind the power button there are 2-4 wires, if those wires get switched, such as accidentally during manufactering then it can cause the computer do burn itself out like that.

[Davedc]

I wish it was something like that, but the case, psu and mobo are all still connected the way they had been in the previous build. It has to be one of the new parts (cpu, ram, video card or one of the drives) or maybe a pwr surge. I did try an old mobo plugged into the psu and the pwr button does still work correctly...the fan runs and turns off after the 6 sec. hold in. Good thought though.
Dave

[Cricket]

Originally Posted by ltmccaul It could also be a problem with the power button on the case. On those very rare occasions, behind the power button there are 2-4 wires, if those wires get switched, such as accidentally during manufactering then it can cause the computer do burn itself out like that.

That's only for AT power supplies, not ATX. ATX power button uses a momentary switch and the wires don't have a polarity...can be attached to the motherboard either way.

Cricket