After some tinkering this afternoon, I may have an issue with the spindle board/motor/choke.

The manual overide doesn't work, so started of by bridging the start connector on the spindle board (it's a Control Techniques ASP-5 with symbols drawn on for the motor/control connections), which would let me up the speed to maybe 50-60rpm, before it would start grumbling/hesitating a lot before either blowing the 13A fuse in the plug, or tripping the 32A ring main circuit breaker.
So I disconnected the main control board, and wired the spindle switch/speed poteniometer directly onto the spindle board. This worked better, however any increase of speed above about midway on the dial, or any sudden increase in speed would again pop a fuse or trip the circuit breaker. The built in ammeter was showing about 1A at slow speed, and as speed was increased, it would rise to about 4A and gradually drop back to about 3A if the speed dial was left untouched. The fuse would blow/circuit breaker trip if the ammeter peaked above 5A. Also during this, the motor was at times a bit grumbly.

Tried disconnecting the motor from the spindle, and current pretty much dropped to zero, and the motor would spin upto max speed with no noise or hesitation. However, after trying the speed control a few times, it tripped the circuit breaker again.

After disconnecting the belt, I tried spinning the spindle by hand, and although it's not super smooth, it doesn't take much effort to turn it, and I would expect the motor to manage to spin it without much effort.


Does anybody know if this is likely being caused by a fault with the board, motor, or choke (fitted inline between the motor + board)?