ga990fx ud3 does not power on

[sdmobo]

My PC won't turn on all of a sudden today. I took the power supply out and checked the voltages with a multi meter and they seem fine. How can I test the motherboard? When I press the power button the fan on the power supply does not turn on. Should I short the power pins or something and should the mobo have any lights if its working?

[mcfly]

I would have thought that you would have to short the pins  to get the PSU to start so you can check voltages properly? But anyway that would be my first port of call.

If the PSU fires up by shorting the pins, I would then check that the power button on your case is working in the correct manner. And if that fails I would take all components off the board, check and re-seat them (RAM, CPU, ect)

If the above fails then its not looking too good unless you can start swapping parts over for known good ones?

[rebbae]

If the 'shorting' works for you then it's the pc-case power button faulty, probably. just for a check, switch the restart cable with the power off/on cable (if that works even). then if you can power up with the 'switched' restart-to-power-up button, it may be the cables/wires fault.
take them out, replace them. if you're okay with soldering a new one, you're good to go. if not, try another pc-case or, a problem less, find someone who can solder the new power button wires. you can use an old router to LAN cable to get the wires, just remember which color is negative and which is positive. hope it yelps.