I've about had it. I can't seem to turn on/off the spindle using Mach3 and the c23 board without crashing Mach3 at all. Right now, I have my spindle wired for turning on/off, and using it's own potentiometer as a speed control. I can take those leads, one is forward, the other is 24volt, and connect them together, and the spindle turns on as you'd expect. I connect those to output #1, which is defined as port 1, pin 1, and the 24 volt lead to the shared voltage in. Then when you click the spindle clockwise button, Mach3 tells the spindle to turn on, but then it crashes. The output relays are enabled, the outputs are enabled. The smooth stepper is set to spindle type 'relay/none' (although I've tried all settings). I'm about to just rig up an external switch that turns off and on the spindle manually, not ideal, but damn, how many hours is it supposed to take to get these things working?