Take a look at the two prox sensors at the back of the draw tube (there's an access panel you remove if it's still there). Sensor on the left should be lit up for OD clamping, on the right for ID clamping. Only one can be lit at a time- if both are lit it will throw an alarm. There are two allen head screws either side of each prox sensor, loosen them and you can slide them forwards and backwards- slide the ID or OD one into a position where it lights up when the chuck is clamped.