Dear Luke and MMDers, Luke proposes a list of player actions and how
easy they are to rebuild. I know this list is going to be inundated
with additions and corrections to the list. Here are mine:
I have found the Simplex to be fairly easy to rebuild except for the
splitting of the pneumatics to access the valves. Still, it's not too
hard a job.
The Amphion player action is essentially what was enhanced to produce
the Ampico action in upright pianos and modified only a little for the
grands. This is fairly easy to restore but, of course, the expression
devices need some advanced understanding. Still, these are all still
fairly straightforward to rebuild.
Luke has the Wurlitzer in the middle of the list. The caveat here
is that if the system uses the die-cast valve bodies, the die-cast
components are a zinc product similar to Zamac. This is notoriously
unstable and frequently the castings are starting to "explode".
I rebuilt one piano where I was able to epoxy two of the valve units
(4 valves each) so that they were essentially nonfunctional but visually
looked good. Since this disabled the end 4 bass and treble notes on an
88-note piano, this was not a problem. If more of the valve units are
deteriorating, then the only fix is to find replacements. I don't know
of anyone who has reproduced these fairly complex castings. The
chemistry is such that about 30 percent of these valves are damaged.
I look forward to other MMDers' additions to Luke's list.