I'm trying to start/stop a spindle in Mach3 using relay board. I don't understand why it isn't working. When I do the "toggle spindle" routine on the diagnostics screen described in Mach3 set up manual I can get my wires to go from 0 to 3.9 volts, and the screen indicates "input 1 " as functioning, but it won't start the spindle. I've tried both active high and low settings. But when I hook up 5 volts, or even 3.3 volts, from a seperate source to the relay's 5 volt input (instead of the wires coming from my BOB), it works. Can anyone explain this or help me? Thanks!