A typical Wurlitzer band organ uses a vacuum system to play the notes
much like a player piano uses vacuum to move the keys. The band organ
has a small pneumatic that operates the keys so to speak that turn on
each pipe when called on to play by a hole in the music roll.

There were several different valves used over the years. One that was
used by Wurlitzer was a unit valve system where a valve is held to a
chest by two screws. These valves were also used by some of the player
pianos made by Wurlitzer. There were several other variations of this
valve but all work on the same principle.

Most player pianos used a pouch with a bleed and a valve to control the
pneumatic. This is explained with pictures in the Player Piano Repair
book by Arthur Reblitz. Anyone that would like to learn about the
operation and repair of the player piano should read this book.

Don Teach
Shreveport, Louisiana

 [ "Player Piano Servicing and Rebuilding" by Arthur A. Reblitz,
 [ (C) 1997 by Vestal Press, Vestal, New York
 [
 [ Also recommended:
 [ "Piano Servicing, Tuning, and Rebuilding: A Guide for the
 [ Professional, Student, and Hobbyist (3rd edition)", by Arthur
 [ A. Reblitz, ISBN-13: 9781538114445, (C) 2019 by Rowman &
 [ Littlefield Publishers, Inc., Lanham, MD 20706
 [ https://rowman.com/ISBN/9781538114445/
 [ -- Robbie