On several occasions I have had the problem of bad switches in Ampico
pianos and a few Duo Arts.

If one has *infinite patience* it is sometimes possible to take one of
these original switches apart, and repair them.  Be prepared for
springs to fly out, etc., but they can be put back.

Usually there is a fiber frame device that cracks.  Either a new fiber
piece can be fabricated using part of an old radio circuit board, or
the original fiber can be glued back together using an epoxy based
cement.  If the brass contacts are bad, new ones can sometimes be
fabricated using parts from an old light fixture or brass of the same
thickness.

This job can be most frustrating, and only works about half of the
time, but it is worth a try.

Bruce Clark