first you ned to check the motor
the motor has
armature 2 wires
field coil 2 or 3 wires
tacho 2 wires
you need to check continuity of all 3. the armature and field have quite low resistance but the tacho is a bit higher
then you need to check the tacho is generating voltage by setting meter on a low ac scale and spin the motor by hand while lead are connected to tacho output
the fact the motor is doing nothing now means something has blown either in the motor or the circuit board
Dave