Wurlitzer photoplayers usually had the action stack that moves the
keys.  Under the keyboard is a set of pallet valves to work the pipe
valves.  It has been close to 20 years since I have worked on one and
some details are hazy as most of my memory has been hazy in these
so-called golden years.

It is a typical stack with a little finger (lever) that is hinged on
the front of the stack.  As the pneumatic closes it pulls the finger
up on the back side and that pushes the key down on the front side.
The finger is long enough to just miss the back side of the fallboard.
The ones I have seen all had unit valves but, knowing Wurlitzer, there
is no set rule.

Don Teach - Shreveport Music Co.