If the construction of the Ampico A spoolbox is similar to my Amphion
88-note action (I think they used a lot of the same parts), then there
is a round-head set screw holding each of the tracker tubes in place.
These screws are on the back side of the spoolbox, directly behind the
tubes.  If I remember correctly, there is a round hole in the back
panel of the spoolbox, and the screw head is accessible from the rear,
through the hole.  The other screws that are visible inside the
spoolbox hold all the parts in place, but don't allow any adjustment.

Bill Luecht