Quote Originally Posted by Mechanic688 View Post
You cannot just use a volt-ohmmeter as certain wires or lines need a jumper or something like that to activate all the voltages of the supply.
I guess the testers have that internally. If you don't use the jumper in the right spot then part of the supply will read as dead.
Mine's just a little rinky dink thing, like any other simple electrical tester, plug it to a plugged in power supply unit and it all comes on, then you can test each connector into the same testers different inputs and test them while it's running