Martin Anderson wrote to the MMD:

> I am looking for a schematic for a rewind mechanism used on a
> Wurlitzer coin-operated player piano, serial number 36881.  The
> one I have uses a 4-in-1 valve.  One I have seen uses two unit valves.
> The piano plays an APP roll.  Any help is greatly appreciated.

I am in the process of restoring this section of a roll player and
making a copy for myself.

The function of these two valves, and the cut-out pouch in the block
above them, is the same as a "lock and cancel" device.  The patent
covering this was posted to the MMD technical archives a number of
years back.  The text of these patents gives the schematic and
description of how the system works.

There is a Vestal Press reprint floating around which describes the
standard "unit valve".  On the flip side of this is the schematic for
the "lock and cancel" registration control.  A photograph (but no
details) shows the 4-in-1 valve unit variation of the lock and cancel.
I may have the unit in my possession that Mike Kitner photographed.

I do not have the exact channeling used for the 4-in-1 variation when
used as a rewind control.  The patent drawings clearly show the 2-unit
valve variation.   Only two of the 4-in-1 valves are needed, the other
two are not used.  From photographs I can see the same cutout pouch is
used as in the unit valve variation.

There are two additional pneumatic switches needed.  One connects
to the rewind lever and is hidden in the side back of the roll frame.
Another controls the vacuum to the stack shutoff.  A slider valve is
used to control vacuum to the rewind system.  These are connected by
a complex set of linkages. The patent drawings and text clearly
describe these functions.

When correctly set up, the main slider linkages has three positions:
Normal Play, Idle, and Rewind.

Julie Porter