In response to John Tuttle's question, I'll provide some general
background information on Wurlitzer Automatic Roll Changers because of
the important variations in manufacturer, design, construction and use.

Wurlitzer used two entirely different changers.  Instruments made 100%
by Wurlitzer contained the "Wurlitzer Automatic Roll Changer"; these
include keyboard-style coin pianos and orchestrions, the Bijou
Orchestra, the Solo Violin Piano and the Autograph expression piano.

Wurlitzer PianOrchestras, which were keyboardless, larger, made
entirely or partially by J.D. Philipps & Sons of Frankfort, Germany but
sold by Wurlitzer, always included 6-roll Philipps roll changers.

The most obvious differences between Wurlitzer and Philipps 6-roll
changers are that Wurlitzer changers are smaller, have the take-up spool
under the roll storage reel, and the paper moves from top to bottom
during play.  Philipps 6-roll changers are much larger, the take-up
spool is above the reel, and the paper moves from bottom to top during
play.  Philipps also made smaller changers with fewer rolls.  The rest
of this discussion pertains to Wurlitzer changers only.

There are two major types of Wurlitzer Automatic Roll Changers -- early
and late.  The most immediately recognizable difference to the novice
is that the early style has a vertical chain on the right side, and the
late style has a vertical shaft.  There are also other minor variations
within each style, as well as several types of rewind cam, vacuum dump
or cutout, tracker bar mounting hardware, ways of attaching the tubing
to the back of the tracker bar, etc.

Early style Wurlitzer changers and the first late style changers have
no pot metal, but most late style changers have a number of pot metal
parts, some of which are almost always broken, expanded or misshapen,
due to intergranular corrosion of the zinc alloy that was inherently
contaminated by the inclusion of lead or tin.  Most changers are
numbered with small numbers stamped into the front or top edge of one
side plate.  My shop has restored and replated about 25 roll changers
of various brands over the years, including at least 12 Wurlitzers.
These have ranged from #402, made in 1913, to #4,879, made in 1925.

The change from early to late mechanism occurred somewhere between
#1,482 and #1,787.  The change from cast iron to pot metal parts began
somewhere between about #1,800 and #2,400.  I use the word "began"
because Wurlitzer first switched a standard group of components over to
pot metal, then went through a period of using pot metal for even more
of the parts, but went back to cast iron for those because the pot
metal proved to be too weak.

Other lightweight changer castings that are sometimes worn or bent are
made of aluminum.  If necessary, they sometimes can be repaired, in
contrast to the pot metal parts, which fall apart if the metal has
deteriorated.  Neither material is magnetic.  If you can't tell whether
a part is made of zinc pot metal or aluminum, dip the end of a wooden
toothpick in a tiny amount of muriatic acid and touch it to the metal
in a non-critical place.  If it begins to fizz, it's pot metal.  If
not, it's aluminum.  (Of course, rinse the part immediately.)

Regarding the scale design and tubing, Wurlitzer changers in key-board
style pianos and orchestrions use standard Wurlitzer 65-Note Automatic
Player Piano Rolls that are 9 5/8" wide.  That scale has appeared in
many references including Bowers' "Encyclopedia" and my "Player Piano
Servicing and Rebuilding," "Treasures of Mechanical Music" and "The
Golden Age of Automatic Musical Instruments."  (The earliest version
of "Player Piano Servicing and Rebuilding" has a mistake regarding the
connection of the automatic register mechanism for the violin and flute
pipes, but this is correct in more recent printings.)  Bijou Orchestras
play 5 1/2" wide Pianino rolls spooled on changer spools.  Solo Violin
rolls and Autograph Piano rolls are each 12" wide.

One feature of Wurlitzer changers that puzzles many people --
particularly if it has been disconnected -- is the shutoff pump.  This
is a medium-size pneumatic (about 4" x 2") mounted left of the changer
on one edge.  It is not a pneumatic that performs a mechanical action
when fed with vacuum.  Rather, it is a spring-loaded pump, which
produces suction when a lever mounted under the bottom of the left side
plate pushes it open.

Its purpose is to shut off the piano at the end of rewind.  Changer
rolls usually have 5 tunes, with shutoff holes at the ends of tunes
1 through 4.  Each shutoff hole triggers a valve that operates the
shutoff pneumatic in the coin accumulator as in any other piano.
However, it is desirable for a piano with a roll changer to shut off
at the end of rewind, before spooling the leader of the next roll,
so a patron may select the next roll before inserting the next coin.
For this reason, the shutoff pump mechanically turns the piano off at
the moment the leader comes off the take-up spool and latches into the
reel.

Tubing from the regular shutoff valve and from the shutoff pump
connects into a block with a one-way flap valve and then to the shutoff
pneumatic in the coin accumulator.  The flap valve directs the vacuum
into the shutoff pneumatic without flowing backwards between the valve
or shutoff pump.  Originally these were tubed with lead that was
cemented into place, to prevent people from disconnecting it and
getting free music.

When we restore a Wurlitzer roll changer, we replace the bad pot metal
parts with accurately-reproduced new castings, and have everything
replated.  Complete restoration is not a job that can be done in a few
hours, but a restored changer operates very reliably.  At the current
time we have a few sets of reproduction castings left, but I'm keeping
them for instruments that we restore in my shop.

If you have a Wurlitzer piano with a roll changer, I would appreciate
your sending me the changer number, piano model and serial number.
I'll eventually publish a list that might be helpful in predicting the
style of a changer in a given piano, and what parts it might need.

Art Reblitz
orchestrion@juno.com