So I've got the machine being quiet now (no buzz).
And I've confirmed the unit does
not try to engage the motor unless switched to Line or Local mode. The second you
turn the switch, the motor does about a 1/4 turn and then there's a visible spark
from
the bottom of the fuse holder. So I'm guessing this must be caps or something
drawing too much power somewhere.
I assume this is with a good fuse in the holder. Without it, the motor should not be
powered at all.
I would try removing the belt so as to remove the load from the motor. And then
check the motor capacitor and starter relay (if there is one).
-tony