How to Manually Turn On an ATX Power Supply

There isn’t a traditional power-on switch on ATX computer power supplies so if you need to test one you need to jumper two pins on the power supply cable. You can use a bent paper clip to act as the jumper. Jumper the green and black wires which are pins 13 and 14 on a 20-pin ATX power supply. More details about ATX power supply wiring can be found at this link.

ATX 20 Pin Power Supply Pinout