I think John McClure may be referring to the monograph by Art Reblitz
"How To Modify Accordions for use in Automatic Music Machines"
published as No. 16 in the Vestal Press Technical Series.  I don't know
where you can buy a copy and while I don't want to part with mine;
contact me if you're stuck, John, and I'll see if I can help.

Michael Woolf
New Zealand