Bill Chapman asks about the "A" Ampico "Play" control disengaging from
the "Play" position: "There doesn't seem to be enough friction to make
it stay where it should be."

This is a hazard inherent in the design.  The "Rewind/Play" pneumatic
shifter spends most of its time in the "Rewind" position so the cloth
takes a "set" and prefers that position.  So, much like an infrequently
used air motor, the resulting "springy-ness" of the cloth in the
preferred position works against remaining in the other position(s).
Several remedies can help with the problem:

1. If the pneumatic has been recovered, the replacement cloth may be
too thick or has aged to the point of being too stiff to function
properly.  Recover with fresh cloth of an appropriate weight and
folding characteristic.  Striker pneumatic cloth is a bit too light,
so "motor" cloth is better.  The material I use is about 0.015" thick,
and although I do not know its origin, the leading edge of the roll is
marked "50" which may have been a stock number used by PPCo.  Somewhat
lighter weights may also work, but I would avoid anything heavier.

2. Introduce some friction into the pivot points of the pneumatic,
primarily the large screw that secures the transmission shift rod to
the center movable board of the pneumatic.  But also tighten the six
smaller screws that secure the spacing "links" at the "heel" of the
pneumatic.  Frequently, enough friction can be generated by tightening
only the "topside" screws.  The ones on the bottom would, of course,
require removing the unit from the drawer.  This action will help keep
the movable board in either of its maximum excursions, but make sure
the screws are no so tight that the pneumatic cannot move at all.

3. Exercise, exercise!  A roll a day keeps the technician away.
This is beneficial for many components, not just this one.  If you
can remember (or maybe leave a visible note), I would even recommend
returning the control to the "Play" position at the end of your
listening session.  If it doesn't want to stay there, devise a "prop
stick" of appropriate length to force it into that position.  I also
recommend leaving the air motor crankshaft in a non-preferred position,
but that is trickier to do so that each bellows gets "equal rest".

4. I normally adjust the rewind brake and spring so that there is
no, or only a very small retarding force, on the take-up spool.  Your
fragile, original rolls will thank you for that.  Tightening by hand
after rewinding is a small price to pay for an undamaged roll.

John Grant