On the left hand side there are four pallet valves.  These tee
into the pneumatic controls for (1) loud pedal, (2) soft bass,
(3) soft treble, (4) silencer.

The silencer is a pneumatic that shuts off vacuum to the stack.
It stops the stack playing but allows the motor to continue driving
the roll forward.

On the right hand side there are lever controls: (1) Play/Rewind,
(2) Tempo control, (3) key stop.  The key stop holds the keys up
when the pianola is playing, so the keys don't move up and down when
playing the pianola.  This is a rail under the front of the keys
which simply holds the keys in the up position.

Paul Rumpf