Hey! I have the exact same machine. I purchased it for peanuts because it had a bad spindle drive board and some problem with the Fanuc 6MB motherboard. I replaced the spindle drive with a KB 4 quadrant drive and replaced the Fanuc stuff with Mach3. I haven't done much with my tool changer, but it sounds exactly the same as yours (20 position with a pneumatic arm). I could also use some documentation on the tool changer to assist in building my own controller for it.