Just hooked some parker/compumotor drives to the existing steppers to play.
http://www.youtube.com/watch?v=dKz81fY1OjY
I am actually running the optos in the drives directly from the printer port. This is just a mock up to see how it runs. I will do a complete job now that I see it works great.
This is the controller that came with it. I need to fix it. really burned a mosfet.