Hello,  Concerning the air motor governor in their later models,
I'm curious to find out exactly how many variations Duo-Art made.
(The model where the tracker tubing goes along the sides of the action,
not through the keys.)

I've encountered three so far and none of them are listed in any of
the technical articles, service manuals or books I've found to date.

Musically,

John A. Tuttle (john@player-care.com)