Turn-on your power supply
Plug-in your 24 pin power supply connector to mini tester
Check LED light it ON or OFF
Plug the HDD con, check +12V, +5V
Remove HDD, Plug p4(p6/p8)con, check +12V
Remove p4(p6/p8)con, plug FLOPPY con, check +12V, +5V
Remove Floppy con, plug SATA con, check +12V, +5V, +3.3V
Do not plug wrong position when you use P4 connector