I have a WS-CAC-1300W power supply that I need to bench-test. I have found the 3.3V, 5V, and 12V outputs on the back but no output from the 42V pin. I'm guessing there is a PS-ON signal to switch on this rail. Can anyone tell me how the 42V output is activiated? I'm guessing there is a pin that goes to ground potential when the power supply is installed or something.