To answer Mr. Taylor's questions in yesterday's MMD.  As usual, Aeolian
picked the hard way to do anything, when it came to the early model of
the 116-note pipe organ roll-reading apparatus.  I have two of these
devices, although I no longer use them, having replaced them with the
newer pouch-and-contact reader boards,  In many installations, Aeolian
did the same thing, when those original units, virtually impossible to
repair easily, became troublesome.

But I did rebuild mine, and they can be made to work, but they remained
troublesome and noisy.  Mine came untouched by any 'restorer', so here
are the answers:

> 1.  What is the pouch material?

Ordinary thin pouch leather, 7/8" active diameter.

> 2.  What connects the pouch to the valve stem--is it a lifter disk
> or leather nut or both?

> 3.  What is the diameter of the lifter disk or leather nut?
> If it is a leather nut, is it glued to the pouch?

The pouch has a 1/2" diameter flat leather nut glued to its center.
The valve stem is a threaded wire screwed into the leather nut at its
bottom end.  The valve itself is only a 1/4" diameter leather nut, the
old-fashioned kind that was turned or milled into a perfect hemisphere,
rather than the new stamped ones.  It was screwed, round side down,
onto the top end of the threaded wire.

> 4.  What is the valve gap?

I can't tell you that exactly.  The lower seat is a hollow threaded
tube about 3/8" in diameter with two 'spanner notches' milled into its
lower end, screwed into the bottom of the valve board.  One can make a
tool that enables one to reach into the narrow space between the top
surface of the pouch board and the bottom of the valve board, and turn
the seat to adjust it till it works okay.  But correct gap is then
'invisible', but I would guess it is less than 1/16".

> 5.  What is the mating surface on the inside (bottom) valve?
> Is it the small cone directly mating on the adjustable brass seat?

Only the spherical lower surface of the leather nut, which
automatically centers itself in the hole in the adjustable lower seat.
There is no stem wire guidance except this self centering effect at the
top of the stem, and the fact that it is screwed to the pouch-nut at
the bottom.

> I have identified one major error in that rebuild which rendered the
> player almost useless.  The primary valve stems had some form of upper
> guide strip...The gouges were not repaired, and under
> the new plastic guide strip, all primary valve channels were
connected,
> via the gouges!

To clarify this for other readers, the system worked as follows:  When
a hole in the paper appears, wind from the pressurized spoolbox
inflates the pouch (with a tiny bleed to atmosphere), lifting the
leather-nut valve.  The upper wooden seat hole, connected to a
pressurized chamber above the valves, is covered by the flat side of
the nut, and the lower brass seat is opened to atmosphere.  A channel
from the center of the valve is thus vented.  This channel is drilled
across the bottom, up the back, and across the top of the pressure box,
ending in a vertical hole in the top board.

The lower end of this hole connects to a tiny rectangular pneumatic,
about 2-1/4" by 7/16", glued to the underside of the top of the
pressure chamber.  When the channel is vented, the pressure in the box
collapses this, causing its bottom board to rise.  A thin rod is
screwed to the bottom board of the pneumatic, and passes up through the
vertical hole to the outside of the pressure chamber, where it actuates
the electrical contact in a separate, unpressurized box.

To seal the normally pressurized channel from the unpressurized contact
box, a strip of celluloid, drilled with holes that closely fit the
actuator rods, is glued across the entire top of the pressure box.
This item is what Mr. Taylor found to be ruined.  Since the channels
are closely spaced, and the top of the box containing them is thin,
fixing this may turn out to be a bear.

When the unit is all fixed, the seal at the leather nut seats and
around the contact rods in the celluloid strip are still imperfect;
these 232 leaks together make a considerable, annoying hiss.

In case Mr. Taylor or anybody else is interested, I have a couple
of the damn things that could find a new home for a _very_ reasonable
figure!

Richard Vance