Does anyone have a schematic or other documentation on the internals
of the Hupfeld Phonoliszt-Violina piano octave coupler that they would
be willing to share?  I'm particularly interested in the version in
the reproduction Violinas, in case the design changed over the years.

Any other internals documentation would also be of interest.  I have
a document by Siegfried Wendel titled "Technische Zeichnungen und
Einstelldaten" and one titled "Spiel und Regulier Anleitung" from
Hupfeld.  The one by Siegfried has a bunch of notes in script on the
first page that are too small to read in my copy.

Lyle Merithew