The buzzing definitely seems to be coming from the
motor. I put a plastic
tool to the casing and could feel it vibrating. However, I can turn it by
hand (clockwise) and see all the gears and striker mechanisms working.
Should the motor be running in the 'Off' positon of the switch, though?
If the motor is buzzing and taking a high current (which blows the fuse),
what about the motor run capacitor (the one on the mechanism chassis
itself, wired to the motor)? Maybe it has failed.
-tony