I saw the post in the MMD yesterday.  I've been working on players
since 1970 and specializing in the Apollo since about 1971.  I'm an
AMICA member since 1976.  I've had many of them and currently have
a recently found, intact Solo Apollo.  They are marvelous players.

There can be many variations of the player systems.  Melville Clark
offered at least three different Apollo player systems, all with the
spring-motor.  On some of the pianos the spring-motor was optional at
extra cost and on some of the larger pianos it was standard equipment.

There were at least three different types of player stacks.  Forward
facing leather covered pneumatics with push rods directly on the key
behind the fall board was the first one.  A cloth covered pneumatic
that lifted up the action and another cloth covered pneumatic that had
a lever system that transferred the power from behind the stack out to
the key right behind the fall board were other variations.  At least
two, but probably all three systems were offered at the same time.

Then there were the Amphion systems that may or may not have used the
spring-motor.  These may or may not have Wurlitzer parts in them, too.
I have seen and worked on pianos that have Melville Clark, Amphion and
Wurlitzer parts that are all original.

The little pouch pneumatics are made of high quality leather and, if
they have been kept relatively dry, they usually still work.  They are
easy to remove, but they'd be a huge labor project to rebuild.  The
valve and seat are easy to rebuild.  It's just a drum shaped and
covered piece that seats on a brass tube ring.  They use felt, rubber
pneumatic cloth and pouch leather.  The wind chests and channels are
sometimes hard to seal, and if they are leaking, can require tons of
shellac, but they will seal up.

The pianos are very high quality.  If you were to provide the serial
number and the size (height) of the piano, I can probably tell you much
more about it.  I have done Apollo pianos for people in other states.
It's much nicer to have the whole piano here, but just a player rebuild
can be accomplished without the piano.

I am working on a registry of Apollo and Melville Clark pianos and hope
to have a questionnaire ready for distribution soon.  I can send photos
of various Apollo systems to those who might be interested.

Thanks,
Jere DeBacker - Jere's Player Piano Co.
Denver, Colorado