How to Test an ATX Power Supply

Items needed: ATX power supply, paper clip, power cable, electrical outlet, the info below

The first thing you should do is look at the 110/220 V switch on the back of the power supply. Make sure it's set to the right voltage for the outlet you're plugging it in to. If you've confirmed the switch is correct for the voltage being supplied and it still will not work, read on.

Now, unplug the power cable from the wall outlet and the power supply. Unplug the power supply from everything in the computer; hard drives, dvd drives, motherboard, everything.

Hold the main 20 pin connector facing you with the clip to your right. The top pin on your left is Pin 1, below that is 2, etc.

Pin 14 is the power on signal wire, conveniently next to that is a ground connection at Pin 15. Break out the paper clip and stetch it out so it's in a U shape with the ends close to each other, put one end in Pin 15 and the other in Pin 14. Put the power cable in to the back of the power supply and plug it in to an electrical outlet. If the fan starts going, it's working, you can test the voltage on the molex connectors at this point if you'd like. If it doesn't turn on, then you've got your definitive answer that it's not working.