I recently made an ebay buy and got myself an old CPM 3020 by ISEL. I didn`t know much about it but heard the hardware (leadscrews and general build) would be solid and well built but the electronics old. I was thrilled will the buy but everyone was correct, the drivers I couldn`t utilise as I just don`t have the skill and couldn`t see a step/dir input (I don`t think there is one despite what someone mentioned in the comments on the video). I also wanted it running on Mach3 so I ripped all the electronics out and replaced them with new digital stepper drivers but kept the current power supply and motors.