Richard Vance gave us an alternate switch to use, I assume for
Duo-Arts.  But for those who would like a switch very much like
the original mechanical Duo-Art switch that pulls on and pushes off,
Player Piano Co. found a bunch of original marine or aircraft switches
made for the purpose.  They are well-made and should last a lifetime.
They also feel as though they have the right push-off force, so it
will hold itself on and the pneumatic will turn it off.

If the switch isn't strong enough to hold the pneumatic open by its own
over-center spring, then the switch could, at any time, just open again
from lever weight or pneumatic resistance, and the motor switch will
stay half-mast, unable to tell by looking if it's on or off.

I strongly recommend acting on this now, as all original Duo-Art
switches are old and fragile, and almost always burned from the motors
back EMF.

Contact PPCo at 316-263-3241 and order one whether you need it or not,
and tape it up in your piano somewhere.  Because it isn't a question if
you will ever need it.  It's when, not if.

Craig Brougher