Yes, as it comes the Spindle Motor Speed Controller is at mains AC potential, however there is an optic-coupler between the Mains device from the pulse circuitry. I have since stripped it out and fitted a 48v Spindle Motor and a new PWM speed controller.

I have also fitted optocouplers, SIL Network Resistors to the Parallel Port PCB, beefed up the complete board with High Temp Electrolytic's to take the full X, Y, & Z limits including a couple of E-Stops.