Hi Lee, i will take a look inside the puck again and see if i can see any problems, it is the kind with a plastic button that presses down in the middle with what looks like 3 arms sat on ball bearings inside, and i assume that when one of these arms is lifted off a ball bearing the circuit is broken and the digitize led should register, but it does nothing.

So i assume it cant be related to the bit/spindle as there is no electrical contact there

regards
Adam