I would like to respond to Randy Hayno's request for Ampico B information.

[ in digest.97.10.12 ]

First, Randy, congratulations on buying a fine instrument and in such good
condition!   Every question you raise has been raised in the past.  As each
new owner/collector comes on board, we get to revisit these issues.  That
keeps us old timers in touch with our beginnings.  We get to relive the
excitement of discovery all over again.  It is still fun!

Your first concern about the soft pedal valve--

> The soft pedal valve was leaky and when I went to remove it I found that
> someone had lost the nuts and spring clamp (which is a backwards one),
> so they glued the valve block in place

More than likely the valve seat inside needs to be reglued.  This is a
common problem with Ampico B valves--the inside seats don't stay glued
down.  Since you have discovered that the unit valve was glued into
position, don't assume some repair person  did that.  The factory glued
soft pedal unit valves   in position.  I would suggest that who ever tried
to fix it previously, removed the nuts and spring clamp only to find the
valve would not come off.  At that time they did no more work and did not
bother to return the spring clamp and nuts.

> What size and threads are these nuts???  My thread
> gauge doesn't have anything to fit it.  Does anyone supply these and the
> spring clamps?

The spring clamp  is also commonly found on "A" stacks in locations where
one block valve is mounted with a stud on either side.  An exact
replacement may be hard to come by.   The studs have rolled threads.  There
has been some recent MMD discussion about this type of thread.  Stud nuts
are the same on both Ampico "A's" and "B's".  In a pinch, until you obtain
replacement stud nuts, two can be removed from the bottom of the expression
units as they are in an abundant  supply there.  Don't loose the spring
clips there!

Your concerns about the drawer modifications--

> Also in the drawer there was a modification made to the Control Valve
> Block.  My block is different than the one in the book.  It has a
> separate nipple to feed the reroll valve "A"  on top.  The book shows
> that valve is fed from the side from pedal suction along with the tracker
> and music roll brake.

Shortly after Ampico B production started, the factory started making a
series of improvements.  Those improvements are not shown in the 1929
Service Manual. Only the very earliest drawers conform to the service
manual.   The modification you speak of  improves reroll and tracker
reliability.

In the initial design, three components in the drawer are feed by one 7/32
supply tube.  The supply is from the pedal regulator.  The three components
are; tracker,  music roll brake, and rewind valve.  Since the tracker and
brake are constantly bleeding atmosphere into the system,  the rewind valve
and pneumatic may operate sluggishly for lack of a strong vacuum source.

To correct this, the _factory_ changed the control valve block and created
a second  source of regulated pedal pressure to the drawer.   Several
versions of this change have been identified, but they all work the same
way.  The bottom line is that valve "A" (page 50  of the service manual) is
isolated from the other two components.  There is no internal channel
within the control valve block connecting Valve "A" with the tracker and
music roll brake.  Therefore...

> There is one more nipple on my Control Valve Block
> than the one in the book.

There is an extra nipple on the control valve block. The extra supply tube
to the valve block is normally at the extreme bass end of the tubing
harness.  It's route from the pedal regulator  to the harness is a
variable.

I am puzzled about your statement..

> The modification I found is that the nipple that is supposed to feed the
> music roll brake was plugged and the brake was fed with a separate tube
> from a tee at the pedal pressure test block.

The normal routing to the music roll brake comes from the control valve
block--either from the top of the block or the back.  The #55 constriction
shown on page 48 of the service manual is actually on the end of the nipple
(straight or elbow) mounted on the control block.  Perhaps this is what you
call plugged? The constriction must be present for the music roll brake to
work correctly.  Recheck your tubing to the brake and look for a
constriction.

> Also what should the
> gauge read on pump suction and pedal suction just before the rewind
> perforation comes along?

There can be some variation in the pump pressure reading.  Usually it must
be above 17 and below 20 for satisfactory results.  The pedal regulator
should be around 15 to 17.

I discussed these modifications in the AMICA Bulletin about twenty years
ago.  That article can be had by ordering AMICA TECHNICALITIES #4
(1978-1980)  see pages 4 and 5.  Technicalities may be ordered from Shawn
Fox, 1319 Pearl, Sandusky Ohio 44870