Hello Bob and Sonja,  Some years ago Vestal Press reissued the 1919
Inspectors' Instruction Book with the 1920 supplement for the Ampico.

Although it doesn't have a complete tubing diagram for your piano it
has quite a number of very useful diagrams, including a description
of the tubing of the expression buttons you describe.

I suggest you try to locate a copy of this book if at all possible
since you are going to have to live with the piano and will doubtless
have occasion to refer to the manual in the future.

In the meantime, if there are any particular sections of the system
that are giving you difficulty I can see what I can find in my copy of
the manual and scan the appropriate diagrams for you.  I don't wish to
part with the book and there may be copyright problems regarding
placing scans in the MMD Archives.  Maybe Robbie can comment here?

Cheers!
Jim Heyworth,
Sechelt, B.C., Canada

 [ I talked with Harvey Roehl about this matter.  He said that he
 [ claimed no copyright on the contents of the old original literature
 [ reprinted by Vestal Press, and he encouraged me to reproduce it at
 [ the MMD web site for the benefit of folks repairing the old
 [ instruments.  -- Robbie