The age of a Pianodisc system is important in setting it up.  The
silent drive unit controls certain functions in the control box.  But
if your system is earlier, they are controlled by potentiometer on the
board.  The sustain trapwork setup has a great effect on performance.

There are setup tables for a short key or long key upright and for a
grand.  I recommend you hire a Pianodisc technician that has knowledge
of old and new calibration to help with your first setup.  There are
adjustments and calibrations that will either give you expression or
just a 88-note player.

Donald Dusenbury