The output of the sensor is going strait to the printer port, no bob, no traces to anything on the
controller board, just a open pin #15 on the rs232 strait through cable, and yes I tested the cable
just in case ( I have been dumb before and grabbed a bad cable  by accident. )

In the pulley configure I did make sure the ratio was 1:1 as the sensor directly reads the spindle.

slot size, on a 2" disk ,I would think that .2" wide would have been more than enough.

I can try another disk if you think it would help. I once saw the calculations some where
but making a new disk will only take a few minutes.

I dont know if it would make a difference, if its easy enough to do then you might as well try I suppose.
Just wondering if you can disable the PWM in Mach, call a M3 and spin the spindle by some other means, maybe even by hand to see if the relay switching is the problem.
Hood