Thanks again to suggestions on how to fix the "Theme" problem on my
Duo-Art.  I was quite surprised that my question about proper raw
pressure from the Duo-Art pump didn't lead to a barrage of opinions.
Back to the problem.

I removed the top cover once again to check if there might be a spot
of glue or perhaps small splinter of wood on the crash valve or its
seat.  There wasn't.  The only way that the Theme expression bellows
was getting high vacuum would have to be via a leak from the pump side
of the box.

I pulled out my stethoscope (the best way to find a leak) and found the
culprit: there was a small leak in the gasket I had placed between the
two halves of the expression box -- very small, but enough to cause the
Theme bellows to collapse significantly.  I sealed it with a bead of
burnt shellac.  The unit is now back in the piano and the expression is
wonderful.

Jim Quashnock