I hooked up the charge pump on the PMDX 126 right away. I manually moved the servo motors with a 12 volt car battery. I could set up the limits moving everything slow. If I hit the stops, (end of travel) it didn't have the power to break anything. I used the original proximity switches with good luck. I messed up one of the encoders. Replaced it from Digikey for $ 24.00. PMDX 126 has provisions for smooth stepper, and a second parallel port. You can double up (Matrix) the parallel ports pins to get more inputs / outputs with one parallel port. I set my computer with Mach. 3 right next to the the cabinet with the BOB & Gecko's while I made adjustments.
The computer will be mounted in the control council when finished. I have remote led lights at the control panel to keep watch on everything. Hope this helps.