Computer does not turn on when pressing the start button

[balajiinau]

I rebuilt a computer using old parts. it was powering up ok and functioning fine. After powering down, it would not turn on again. I found that the LED on the wireless card which goes on when power supply switch is turned on, was not glowing.
I suspected the PS and i claimed that on warranty and got a new one.
once this was installed, the computer worked ok.
Again the same thing has repeated. there is on light on the wireless card, and no response to the power on button.. I jumpered tje PS and it works.
Do I have a dead MB??
Please help guys.

 

[nissanman]

could be an issue with the motherboard. It might not be sending the power on signal to the PSU.

but first things first. What are the specs of the PC? and what is the wattage and brand of the PSU?

 

[balajiinau]

specs

Gigabyte GA-EP35-DS3P
CPU: Intel Core 2 Quad Q9300.
RAM: 2GB DDR2 800.
PSU: Thermaltake ToughPower 650
5Video Card; 8600GT (GV-NX86T512H) (512mb)
HD: W.D. Sata II 640 GB.
Pioneer Blu-ray Combo.

 

[nissanman]

Have you checked if all your cables are connected correctly? The fact that you can power up the PSU by jump starting it tells me that it is not the problem here and a thermaltake 650watt is more then enough for that system. If all the cables a correctly connected then id suspect a faulty motherboard. Is the motherboard still under warranty? If it is, Get a replacement and see if that helps.

Edit. test the PSU out in another PC if you can. Although i dont think it is the problem, its best to try it out.

 

[balajiinau]

I think the wiring should be ok, sinceit was working fine for a couple of days. Unfortunately the MOBO is out of warranty and i dont have a spare one. will need to look for an alternative.
Cheers

 

[nissanman]

Just make sure the PSU is 100% working before hand. Because i could be wrong and it could be the PSU. If you know anyone with a spare PSU, id try that out. Or try the PSU in a different PC if possible. If it doesnt work with a spare power supply installed then it must be the motherboard.

 

[mtd2000]

Discharge

You may have an over charged capacitor, unplug your power cord from the back of the power supply and hold in your button (power on button on case) for about 10 seconds or so, release and plug cable back in, see if helps.

 

[mailpup]

FWIW, I once had a similar but intermittent problem with a Gigabyte P35-DS3R which is similar to your motherboard. For awhile I got around it by shutting off the power to the PC at the back of the PSU for several seconds and it would start normally. Of course, the PC was off when I switched it off. After swapping every relevant part with a known good one, except for the CPU itself, I replaced the motherboard and the problem went away.

 

[balajiinau]

Thank you guys. I will try all your suggestions tonight and let you know the outcome.