Before you start to work on the motor, MAKE SURE THE POWER IS OFF. Always turn the power off at the electrical service entrance breaker box or fuse, to prevent electrical shock.
FAILURE TO START
1. Check for blown line fuse or tripped breaker. 2. Allow motor to cool and try to reset. 3. One of the most common problems in a woodworking shop is a build-up of sawdust in the motor, especially with open drip proof motors. Give the motor a shot of air to blow out the sawdust, nine times out of ten this will get the motor to start again, to fix the problem the motor should be replaced with a totally enclosed, fan cooled model.
MOTOR MAKES A HUMMING NOISE
When there is air pressure in the tank 1. Drain the air pressure from the tank and try to start it again - If it starts, the airline check valve is probably bad and needs to be replaced.