MMD QUESTION:
There are a few sub assemblies located on top of the stack that are
puzzling me.  One has a wire going to the transmission frame attached
to a spring closed pneumatic that doesn't seem to serve any purpose at
all.  And for the life of me, I can't figure out the shut-off circuit.
I know it's triggered by the first T-bar hole, ditto with the end of
roll re-roll triggered by number 75 T-bar hole.  I recovered that
trigger pneumatic and I see how it works easily enough.

ONE POSSIBLE ANSWER:
The Wurlitzer piano depending on year had two pneumatics to the left of the
roll changer.  Some had one.  The large one that has a wooden finger is
snapped open when the roll finishes rewinding  and works the pneumatic in
the accumulator to shut off power.  The stack vacuum is spilled into the air
with a valve on the right side of the piano on the same board with the
changer during rewind so that pneumatic on the left side of the changer
becomes the only source of vacuum to shut off the accumulator.

The little pneumatic with the wire going to the transmission frame is a
helper pneumatic found on the later roll changer pianos.  Identical roll
changer pianos in earlier production did not have this pneumatic.

Hope this helps.
Don Teach