It's not a difficult device to operate, but it sure is handy. In their latest article, PC Perspective takes Ultra's Power Supply Tester for a spin. With all the problems a bad Power Supply can cause, a PSU Tester is a great thing to have if your in the computer repair business.
"The specs are quite simple as you would imagine, with an audible beep that lets you know whether or not the power supply has powered up. If you hear the beep the power supply has indeed powered up, if not and you have it connected to a wall outlet and have any switch that might apply powered on, then it sounds like you need a new PSU."