Hi Robbie -- I have worked on two or three electronic Wurlitzer
players, and I may even have a manual somewhere.  The main problem
I recall is that the die-cut neoprene valve strip or "plate" -- which
is punched out to leave individual strips, each strip of which kept
air from passing through its tracker bar hole -- was glued onto the
inside of the tracker bar, and over time this tracker-bar sized strip
"migrated" to one side, opening all of the holes and depressurizing
the system.

It seems to me that the tracker bar holes were normally closed, but
somehow atmospheric pressure entering the perforations pushed open
these little neoprene "doors" and in so doing shorted a pair of
contacts to play the notes.  There may be another element here which
I do not recall.

Without examining one to refresh my memory that is all I recall, except
that I was able to get one instrument (without the above problem)
working fairly well, but the customer chose not to continue work on
the other.

As I remember, these were made by Baldwin Piano and Organ Co. in
Conway, Arkansas, who, after they went out of production, still sold
parts for them for some years.  Not sure, but I think they were built
under the Dale Electronics patents.

Larry Broadmoore