Hi All;  Some of you have asked why I wanted some old "rocking levers"
for my MIDI record strip, and thought I would detail it here.  I bought
a QRS MIDI record strip at the same time that I installed the Piano-
mation unit in our Foster player which is used for the creation of
Tempola rolls.

I mounted the MIDI strip under the keys as QRS recommended, but I soon
discovered it would not operate when the pneumatic player action was
operated, because the falling force of the keys wasn't enough to
operate the strip.  I realized that it had to be operated by the piano
action itself before it would be able to do both tasks.

The next thing I tried was to mount the strip upside-down on top of
the sticker rail between the action and plate, using tiny "L' brackets
mounted on the stickers to reach back to it.  This worked, but was
inaccurate, with no way for fine adjustment.

The piano has a single valve Standard action, so I removed the head and
mounted the strip on top of the stack right in front of the pneumatic
fingers.  I grabbed the damper levers from some old upright actions in
the parts pile, removed all the damper springs, and inserted capstans
in one end.  The felted end of the damper lever rides on top of the
whippen, (which is rather long, being a player piano), mounted to the
player stop rail.  The other end has the capstan which contacts the
record strip.

The primary problem with a mechanical record strip is that the contact
doesn't have enough travel in relation to the piano key or whippen.  If
it is adjusted to be instant in turning "on", the whippen will bottom
out on the MIDI strip and will not be able to move up its full stroke
and the jack won't trip.  Conversely, if the strip is adjusted for full
throw of the whippen, the whippen has to go up halfway before the MIDI
strip will register the note.  This results in a very sloppy MIDI, hand
played or roll played, due to all that lost motion.

I have finally solved this problem.  The lever rides on top of the
whippen.  When the key is depressed, the lever pivots, and the capstan
presses on the MIDI switch.  However, there are small jack let-off
springs screwed over the capstans that come within 1/16-inch of the
MIDI switch.  This also keeps prevents the lever seated against the
whippen from bouncing.  It also will turn on the switch with very
little movement.  As the spring bottoms out on the switch, the spring
compresses until the whippen has finished its stroke.  The strip
lets-off very quickly, due to the spring pressure.  The leverage of the
lever is such as to have plenty of power to do this without making the
piano sluggish or stiff.  The capstans are used to adjust the springs.

This took a week and a half to build, but the performance is equal to a
good quality keyboard.  Now all I have to do is to insert elbows in the
pouch board, in place if the old Standard junction board, re-tube the
tracker bar, and I will be able to see how well it will read rolls.  I
doubt if my creation will rise to fame like the QRS marking piano did,
but we are very proud of it anyway.

Cheers,

Andy Taylor
Tempola music rolls