Wondering how I remove it? Standard cheapo Chinese BOB with the 12v opto inputs there are about 5 inputs. Ive wired up a photo sensor to the 12vdc and the output directly into the BOB input. The index indicator goes on and off with the single tab that runs through the sensor, its sitting on the main chuck shaft.

So it works of kind. I expect at speeds it might be accurate. What I dont understand is why the spindle speed DRO shows a positive figure when the machine is not running. Currently it sits at about 84rpm to 140rpm when the chuck shaft is not moving. I have considered putting another opto in the circuit. But that seems wrong. Debounce - makes no difference. My lead from the sensor to the BOB is shielded, and the shield is earthed at one end only. Its weird and I am out of ideas. I guess, in a perfect world, the DRO would sit at zero when there is no movement, and rise when there is actual speed. Has anyone acheived that or is this just a poor part of Mach 3 I need to accept?

I know this will be common but was also unable to see any fixes on here. I do plan to thread with this machine.