Hello -- As a footnote to John Tuttle's excellent information on the
operation of Classic player pianos, I'll describe an addition I made
to my pianos, which are a Classic and a Classic-built Baldwin
(identical in mechanisms).
The automatic reroll is quite sensitive, and often I would be dismayed
when a roll with a slight imperfection -- a wrinkle, tear, hole or
gapping of the paper -- would suddenly get rewound before the end.
The control is a small vacuum/electric switch found at the upper left
corner of the spool box, obvious when the lid is lifted.
The switch can be adjusted a bit to reduce its sensitivity, but I put
an on/off switch into the circuit right there to completely disable the
auto-reroll when desired. Happily, I found that a hole had been
punched into the roof of the spoolbox right by the left end. I mounted
a pre-wired toggle switch, available at Auto Zone or Advance Auto Parts,
using small electrical connectors that Radio Shack carries.
Now with each piano, if I suspect I'm playing a roll with "issues",
I can reach into the spoolbox in the upper left-hand corner and flip
the switch to off. I just need to remember to push the reroll switch
at the end of play.