I have two vibratory case tumblers. One's made by Lyman and the other ones made by Midway. Both of them are atleast 12 years old or more. When I plug them in instead of going into vibration mode and tumbling the cases I just hear a quiet hum coming from the motors and that's about it. Can these electric motors be fixed for a reasonable cost or should I just throw them out and get a new case tumbler?