There has been much discussion about tracker mechanisms and rewind
problems.  We decided it is time to jump in!

Tracker bar shifters --

Tracker bar shifters are designed only to align the tracker bar with the
edges of the paper.  They do not align the music roll with the take up
spool.  Because of the variation in thickness of the spool ends, there
can be tracking problems regardless of where the tracker bar may be.
Because the roll is moving quite slowly when playing, it will usually
feed on to the takeup spool OK, BUT, on the high speed rewind, the paper
tends to follow at right angles from the takeup spool to the roll spool
and may try to climb the edges of the roll spool.

In the past, we have converted tracker bar shifters to roll spool
shifters to insure better alignment of paper on rewind.  The takeup spool
must always be aligned with the tracker bar.  To achieve this, measure
the distance from the spool box sides to the inside edge of the flange
and split the difference, if there is any.  Adjust tracker mechanism
accordingly.  If the change is made from tracker bar shifter to roll
shifter, the tracker bar must be centered and locked in place.  Tracker
systems that shift upper and lower spools do not correct for
misalignment.  Individual adjustments must be made to the upper and lower
spools, based on roll spool thickness.

Rewind problems --

Because many of our jobs entail total restoration, we religiously polish
and lacquered all brass components.  After restoration, we normally keep
the instrument in our shop and play it a while to ensure proper operation
and allow for re-regulating after compression of felts, etc.  During this
time, we would usually use recut rolls to avoid wear and tear on our own
collection.

On one occasion, the customer called us several days after delivery to
complain about the rolls being torn on rewind.  After investigating the
problem, we found that the lacquer caused a strong static cling when
_original rolls_ were rewound.  (Her climate was drier than ours.)
Removing the lacquer solved the problem!  We no longer lacquer tracker
bars!

Fishing pole trackers --

The fishing pole tracker mechanism apparently was patented by the Brand
Tracker Co. and most used two paper sensors (Simplex, etc.)  These
mechanisms were designed to be disengaged during rewind.  The sensor
fingers are pulled from the paper and the small shaft that the fishing
line rolls up on are stopped, thus locking the tracker in its last
operating position.

If the rewind operation is halted by shifting into play position, the
fishing line will unwind and cause a sudden misalignment of roll and
takeup spool.  If you then quickly shift back to rewind, you could cause
serious damage to the roll, usually on the left side.

It is possible to reduce this misalignment by installing a screw on the
left end of the spool box that will extend over the fishing pole
(operating lever) and stop the upward travel.  The screw must be located
just above the normal operating position of the fishing pole. (A little
piece of tracker bar tubing over the screw shaft will cushion it.

Misalignment --

Any misalignment of the upper or lower spools and tracker bar will cause
tracking problems, especially on rewind.  Therefore, measuring and
adjusting  should be done to make sure components are not only parallel,
but also on the same plane.  To check this,  make sure both ends of the
spool are the same distance from the front of the spool box and to the
top or bottom of the spool box. Shimming and/or inverting of shaft
support bushings will help to reduce shaft drooping.  The tracker bar
must be checked in the same manner.

Warped tracker bars -- Some old tracker bars originally sealed with great
gobs of putty have warped.  This condition must be corrected.

Early Aeolian Tracker System --

Many years ago we were called to check a Weber Upright pumper that had
tracker problems.  The tracker consisted of a series of narrow sensor
holes above the playing holes on the tracker bar.  They were offset from
the playing holes.  The theory being, if the roll shifted, it would open
a tracker sensing hole, forcing the tracker to readjust.

Theory is not always true!  In this case the tracker pneumatic had a
balance spring to help assist in the operation.  When a program roll was
played, and there was a break between compositions (no playing notes),
the spring would push the tracker mechanism to a new position.  When
playing notes again passed over the tracker bar, tracking would resume,
but the roll had shifted one full note to the right.  Now, the roll could
not find room on the takeup spool, and was out of alignment for rewind.
A simple spring adjustment solved the problem.

This is a lot of wind, but perhaps it will help solve some problems.

Bob & Sonja Lemon
Lemon's Player Piano Service
Sacramento, CA

 [ "Speedy techs keep their motors running!"  Thanks, Bob & Sonja!
 [  -- Robbie