Hi Gary, There's no magic here. Looking at the front of the tracker
bar you see one long row of holes. From left to right they are
numbered 1 through 88. Each hole corresponds to a note on the piano
from 1 through 88.
Each nipple on the back of the tracker bar is connected to a valve
on the player stack. They go in order from 1 through 88, just like
the notes on the piano. In other words, they are tubed in sequential
order from 1 through 88, with number 1 being the lowest note and 88
being the highest note.
Typically, there will be from 1 to 5 other holes in the tracker bar
(in a standard 88-note player). If the bar has two sets of offset
holes on the extreme left and right ends, they will be connected to
a tracking device. If there is only one hole on the extreme left and
right, they will likewise be connected to the tracking device. If
there are no holes on the extreme left and right edges of the tracker
bar, you have a mechanical tracking device in the unit.
It should be noted that these holes on the extreme left and right
edges of the tracker bar are 'outside' of the edges of the paper roll.
Those holes are actually the 'eyes' of the player piano and they 'look'
at the edges of the roll. When the tracking device is working
properly, the 'eyes' will 'see' that the paper is not centered on the
tracker bar and the tracking device will automatically adjust the
position of the paper roll so that the 'eyes' are all opened an equal
This leaves only one other possible hole. It is to the left of the
long row of 88 holes. It's usually bigger than all the rest of the
holes. It is in what is referred to as the No. position. It gets
tubed to the automatic sustain device. Typically, there is a switch
between the auto-sustain hole and the auto-sustain device. That switch
is typically in the spoolbox, on the left hand side wall.
Naturally, if the switch exists, you need to run a tube from the
auto-sustain hole on the tracker bar to one side of the switch, and
the other port on the switch gets tubed to the auto sustain device.
For more information about tubing a tracker bar, see:
Hope this helps.
John A. Tuttle