Plate is Jammed
Most disposers have an opening at the bottom of the housing. If the shredding plate is stuck, insert either a disposer wrench or a ¼ inch Allen wrench into the bottom of the disposer and wiggle the shredding plate back and forth until it moves freely. If the disposer does not have an opening at the bottom, insert a broom handle into the drain opening and try to wiggle the plate. If the shredding plate is not stuck, or the disposer motor still hums after you free the plate, this indicates that the motor is defective. The motor is not repairable—if the motor is defective, you must replace it.