Ed Gaida wrote

> This should come under the heading, "If you haven't run across one
> yet, you're gonna".

These pianos were found everywhere in the 60's.  I have had to repair
several of them.  The most likely problem is the main transformer, which
is left on 24 hours a day unless you unplug the piano.  It is usually
just plain dead.  My elect organ service man can order replacements for
now.  The units worked well but don't play too many marimba rolls on
them .  When they were new the stores played "The sweetheart Tree" all
day long at the malls.  Those notes burned up the solenoids if they
marimbaed too much.

I have had the tracker bar apart.  Interesting piece of design.  There
are no diaphragms.  the tracker bar is about 3/8" thick with perfect
round holes that go up to the square hole at the paper side.  Each hole
has a perfectly formed rubber piston with a square on one end that fills
the tracker bar hole so that when at rest the rubber comes within a
thousandth or so of touching the paper.  At the interior end of the
tracker bar hole cylinder, is a set of contacts that are pressed by the
rubber pistons when the hole is opened by the roll.  It is a very good
system.  However, at 20-30 years old, the contacts get dirty. Also, if
someone sprayed WD40 or other lubricant into the tracker bar holes
because they did not return,  none of the pistons work until they are
removed and cleaned.  HOW DO YOU THINK I KNOW THIS?

Other than this the most likely problem is the lost motion on the
solenoid to wippen contact point.

Good luck repairing them, guys

DL Bullock Piano World St. Louis