[HAM] Need Help Fixing B-3.....

[Frank Bobey]

  Hello Everyone!   I am having a major problem with our B-3... When the
volume pedal is all the way down (soft), or most of the way down it
makes a very loud low pitch distorted sound...Sounds like the woofer in
the Leslie is gunna shred...When you turn it up with the pedal it
performs normally. It just acts up when the expression pedal is low or
all the way down.  Anyone have any thoughts on what this problem could
be??? Thank You..  Frank Bobey