... Tester Description: 1) Turn-on your power supply2) Plug-in your 24 pin power supply connector to mini tester 3) Check LED ... light if ON or OFF (+5V, +12V, +3.3V, -5V, -12V, +5VSB ... /24pin(ATX-connector) 2) Voltage test: +12V, +12V, +5V, -5V, +3.3V, 5V Stand by (SB) 12V, power Good(PG) 3) Connectors: Floppy, HDD ...