Hello, I found your great site on the Internet, sorry for my English.

My question is as follows: I have a Duo-Art player piano but the box
which switches off and on the note holes under the Duo-Art expression
holes (the first and last four notes on the tracker bar) is missing.

How works this box?  Is it easy to make it at home?  I found no
information about this part.  I mean this one shown at

  http://www.musicrolls.com/duo-art/index.html 
  http://www.musicrolls.com/duo-art/half_d-a/100_0385.JPG 

Best regards,
László Simon
Hungary

 [ See also http://www.musicrolls.com/duo-art/d-a16-17.jpg 
 [ The handwritten note at the bottom right says, "Some models --
 [ like Steck Duo-Art -- have no nipples to which to attach the 8 notes
 [ (4 treble, 4 bass) of the piano at the tracker bar.  Likewise, the
 [ stack is eighty notes.  The dynamic box is there so the occasional
 [ non-expression rolls that play those notes won't activate the
 [ expression."
 [
 [ Could someone please explain this statement to Laszlo?  Where can he
 [ find plans to construct the missing pouch switch units?  -- Robbie