I took ownership of this about a week ago and I've already spent some time chasing the wiring and figuring out what components to order. I decided on an AKZ250 Mach3 USB controller (leafboy77) and already ordered it, plus 3 stepper drivers to go with it.

I am planning to use the existing spindle driver which is a Sprint 400 unit.

I have a question about the control signal going to the Sprint 400, the manual says 0-10V. Does that mean pulse with modulation, or literally 0-10V as if it were potentiometer control?