1. Easy to check ATX, BTX or ITX power supply 2. Voltage source: 20 / 24 Pin (ATX-connector) 3. Voltage test: +12V, -12V, +5V, -5V, +3.3V, 5V stand by (SB), 12V power Good (PG) 4. Connectors: Floppy, HDD, CDROM, SATA, 4 Pin (P4), 8 Pin (Dual-CPU), 6 Pin (PCI-Express) 5. Plug power supply 24 Pin and P4, P6 or P8 into the corresponding jacks of the power supply tester 6. Turn on the tester, you will hear "DuDu" sound, if there are no flashing numbers then the power supply functions normally 7. If a certain voltage signal is not detected or voltage is out of normal range, the buzzer will make long "DuDu" sound and corresponding voltage or PG value is flashing, then the power supply is failed
