Ive pulled the back off the FrankenCNCRouter, and quite surprised by what ive found!
As far as i can tell, the box on the bed is just motor drivers, My knowledge of electronics leaves a lot to be desired, but as far as i can see this is a line of beefy transistors?, a line of VERY beefy resistors mounted on the bed to disperse heat, and a few other odds and sods (regular reistors, diodes and a big cap)
The 6 white terminal pins to the centre go directly onto the stepper motors (which are 8 wires each, but two are doubled up on the pins, pressumably common coil connections?)
The 15 pin serial connector appears to have one pin per motor pin, and a couple of extra ones (power out to the control pad, ground, and for the tool lift solenoid?) This leads me to conclude that all the processing is done at the other end of the serial lead.
I conclude that the box on the bed allows the lower serial voltages, to control the beefy 12V, 5A peak supply on the motors yes?
Would it be a reasonable expectation to be able to work out and wire these 15 pins direct to an arduino and try and use the existing driver hardware, probably with a modified AFMotor driver library (as that is what i have used in the past), or