He says he has a voltage reducer but not which kind. If I were him I would first probe the output of the reducer (what ever kind) with a voltmeter to see if it is the problem.
Truckernix is right, no vibrator, we 'fuse blowers' call them choppers, it will not work. If you heard 'motor boating' before it went then the big electrolytic capacitors in your power supply is most likely your problem.

Six volt guy living in a twelve volt world