Is impeller shaft broken? Is there string preventing impeller from turning? Is there a rubber bushing on each end of the shaft? Does each rubber bushing sit correctly in its proper holder? Is the magnet still in fact glued to the impeller, so that the plastic vanes are actually spinning when the magnet spins? Is there any electricity getting to the motor, so you can hear it hum or feel it vibrate (ie, no internal break in electric cord).
