What am I doing wrong here? Working on retrofitting my plasma table with all new electronics, but I cant get the old optical switches (homing for X and Y) to work. They have 3 wires. I figured out which ones are power and ground and put them their own 5v power supply. The last wire should be a signal wire that reads 5 volts when the light beam is detected or 0 volts when the beam is broken, no? I have the signal wire hooked up to my meter, but the voltage doesn't change when I break the beam. Fairly certain they work. I doubt both of them would go bad at the same time. The old manual from the machine says they run on 5 volts, but I looked up the part number and the specs have them at 10 volts. Think I should order a 10 volt power supply? Every other optical switch I've looked up runs on 5 volts, so I assumed mine would too.