Hi All,  In response to Luke Myers' posting about the Aeolian 'Finger'
Tracking System, there are some things you can check which should help
solve the problem of the rolls getting damaged during the Rewind cycle.

As a preface to the following, in a perfect world, the automatic roll
tracking system is unnecessary. However, due to things like humidity,
dryness, improper forward roll drag, slight misalignment of parts
within the spoolbox, slightly damaged or curled roll edges, poorly cut
roll paper, or poor roll care, roll centering devices were invented to
help keep the holes in the roll aligned with the holes in the
trackerbar. For reference specific to the Aeolian Tracking System with
Tracking Fingers, check Page 20 of the 1925 Duo-Art Service Manual.

One, disconnect the linkage from the tracking bellow to the cam on the
transmission at the tracking bellow. Check the static position of the
two bellows with no vacuum applied. If one bellow is open more than the
other, correct the problem. The two bellows must be balanced when at
rest.

Two, (with the linkage still disconnected) remove the two signal hoses
at the tracking bellows and seal the nipples with tape. (You can also
disconnect the tubing from the Neutralizing Pouch Block and plug the
hoses.) Then apply vacuum to the bellows assembly. I normally do this
by mouth, using a short piece of tubing. If there are no leaks in the
bellows, they will be closed an equal amount -or perfectly centered. If
one bellow is open even a slight amount more than the other, find and
fix the problem.

Three, assuming that both bellows are closing an equal amount,
reconnect the signal tubing from the tracking bellows to the
Neutralizing Pouch Block. Disconnect the tubing from the Neutralizing
Pouch Block to the tracking fingers and seal the nipples on the block
with tape -making sure they are completely closed. Using a 'T'
connector and two more small pieces of tubing, connect vacuum to the
Tracking Bellows and the Neutralizing Pouch Block, and test again by
mouth. What you're testing for now is leaks in the Neutralizing Pouch
Block. If the bellows remain centered, proceed. If the bellows do not
remain centered, find and fix the leaks in the block.

Four, Remove the 'T' and connect vacuum only to the Tracking Bellows,
leaving the vacuum supply to the block 'open'. (This simulates the
condition of the system during Rewind.) Apply vacuum by mouth. The
bellows should stay centered. If they do not, that indicates a leak in
one or both of the pouches inside the block. Replace if needed.

Five, disconnect the tubing from the Neutralizing Pouch Block to the
tracking bellows at the block and using a straight tubing connector,
connect the tubing from the tracking bellows directly to the tubing
from the tracking fingers. Here you are bypassing the Neutralizing
Pouch Block and checking the integrity of the seals on the tracking
fingers. Again, apply vacuum by mouth to the tracking bellows and note
the position of the bellows. They should still be centered. If not,
replace the leather seals on the fingers. If everything checks out
okay, reconnect the linkage from the tracking bellow to the cam on the
transmission, reconnect all of the signal tubing and the vacuum supply
to the block.

Six, check the position of the tracking cam. (Refer to Page 20 of the
1925 Duo-Art Service Manual.) Put a known good roll (11-1/4" wide with
straight flat edges) in place and connect it to the take-up spool.
Advance the roll about two full revolutions by hand. Loosen the screws
on the tracking fingers and move them away from the edges of the roll.
Note: The right roll chuck shaft should be at the center of the
tracking cam when the tracking bellows are centered. If the cam is not
correctly positioned, adjust the linkage between the tracking bellows
and the cam accordingly.

Seven, positioning the tracking fingers. The tracking fingers should
almost touch the edges of the paper. Generally speaking, it's a good
idea to leave 1/64" (0.015") of space between the fingers and the edges
of the paper. After positioning the fingers, tighten the screws that
hold the tracking fingers in place.

Eight, assuming that the fingers are correctly positioned, advance the
roll around by hand until you can see how the perforations in the roll
are lining up with the holes in the trackerbar. If they are lining up
correctly in the center part of the roll, you're done. If not, use the
adjuster in the linkage between the tracking bellows and the cam on the
transmission to position the roll so it opens the center holes in the
trackerbar 100%. Also, if this action must be taken to achieve correct
hole alignment, you must readjust the tracking fingers because moving
the paper in one direction or the other will cause the fingers to be
incorrectly positioned in relationship to the edges of the paper.

Nine, turn the system 'on' and run the music roll for 10-15 feet at a
relatively slow tempo of 20-30 to see if the roll is tracking well.
Slight adjustments can be made, bearing in mind that for best
performance during Rewind, the tracking bellows must be centered during
the Play mode. If all goes well, play the roll to the end, keeping an
eye on the tracking bellows. If they are noticeably favoring one side
or the other, it could be the music roll. Rewind the roll by hand and
try another roll. If the problem persists, there is a leak (or
imbalance) somewhere in the system. Start over, and test everything
again.

In closing, when the system goes into Rewind, the Neutralizing Pouch
Block cuts off the signals from the tracking fingers to the tracking
bellows. And, even though the signals to the tracking bellows are cut
off, the bellows are held in their center position by the supply vacuum
-which is present during both the Play and Rewind cycles. This is why
it's so important that the system be in perfect balance. If the
tracking bellows are constantly tracking to the left or the right
during Play and then they are perfectly centered during Rewind, one of
the edges of the roll could get damaged. Also, if the tracking bellows
are moving at all during Rewind, there's a problem with the
Neutralizing Pouch Block.

Lastly, there are a few other possible problems with the Aeolian
tracking system that were not addressed here. One is wear where the
right roll chuck shaft makes contact with the cam. It's a good idea to
put a little lithium grease at the contact point to reduce friction.
Others include the tension of the reroll brake, the speed of Rewind,
and the tension of the spring on the left roll chuck.

See attached images for more detail.

Musically,
John A Tuttle
Player-Care
Brick, New Jersey, USA

P.S.: From Luke's posting, it sounds like the neutralizing pouch block
is either not functioning correctly, or it is missing, or it has been
bypassed.  The tracking bellows should not move during Rewind.

 [   Information from Duo-Art Service Manual
 [ http://www.mmdigest.com/Attachments/18/08/10/180810_060852_tracking-device.jpg 
 [   Parts of the Aeolian tracking system
 [ http://www.mmdigest.com/Attachments/18/08/10/180810_060852_tracker-parts.jpg