/ Sign-up
Your question

Computer won't turn on, motherboard light is on

  • Power Supplies
  • Computers
  • Motherboards
  • Sound Cards
  • Components
Last response: in Components
September 23, 2011 5:39:41 PM

A family member recently broke the audio port on my motherboard by tripping on a wire. I purchased a sound card to resolve this issue, i dismantled the computer after the audio port was broken because I thought I had to replace the motherboard. A very small screw fell into the top of the PSU when i was taking the pc apart, I removed it by shaking the PSU lightly and letting it fall out the top. Upon assembling the computer again with the new sound card installed I found it would not power on. The light on the motherboard turn on and stays a solid green but the pc won't boot. Can anyone offer any advice on what to do? Could the small screw have somehow broken the PSU? It's a Corsair 850 watt PSU aswell so it's pretty decent and I am astonished if that is the problem. Thanks

More about : computer turn motherboard light

a b ) Power supply
a c 123 V Motherboard
September 23, 2011 5:43:45 PM

remove and reseat the sound card.

Try that

If it still doesn't boot, remove the sound card and try booting.
September 23, 2011 5:57:35 PM

Yeah i tried that, anything else? Is it likely that a small screw (the ones used for srewing in a motherboard) could break the PSU? It was only in for a few minutes, I gently shook the PSU untill it fell out the top. It rattled around inside a bit but I will be amazed if that broke it.
a b ) Power supply
a c 124 V Motherboard
September 23, 2011 7:43:13 PM

Although very unlikely, I suppose anything is possible. The best way to check your PSU is by using a digital multimeter.

Orange = +3.3 V
Brown = +3.3V
Blue = -12V
Red = +5V
Yellow = +12V
Green = +5V
Purple = +5V (standby)
Gray = 0 to +5V (zero when powered off, upto +5V when the case switch is turned on)

Assuming that the system was still working after the audio port broke, the next thing that comes to mind is a short circuit. To test this theory, breadboard your system.

1. remove all hardware from the mobo, except for the CPU/Heatsink
2. remove mobo from case, and place it on a non-conductive surface (wood, cardboard, etc)
3. remove the PSU from the case (this makes step 5 easier)
4. insert one stick of RAM
5. connect the PSU cables (24-pin and CPU)
6. connect your monitor to the mobo, or install a GPU, then connect the monitor
7. using a flathead screwdriver, jump the PWR_SW pins to turn on/off the power to the mobo.

If the above steps don't work, try moving the RAM to a different slot. Repeat until all RAM has been used in all slots. For example: [CPU] | _ _ _ ; [CPU] _ | _ _; etc.