[ Bob Bickers wrote in 130918 MMDigest:

> The roll drive system stops and starts while playing a roll.
> I checked all the usual, easy-to-get-at stuff but it needs an
> expert's touch.

Hi Bob,  I'll put forth a theory about your Ampico "B" roll stop/start
issue and you can decide whether to look into it further yourself or
continue to seek a technician in your area.  First, I have some
questions:

A. Does this stop/start cycle happen on a regular basis during play
and is the "start" vs. "stopped" timing roughly ten-to-one?  If so, it
sounds like the brake on the take-up spool, which is _supposed_ to be
active only during reroll is, none-the-less, remaining active during
forward play.  See further discussion below.

B. Does the issue persist throughout the entire forward playing of the
roll?  Or,

C. Is there a point, maybe several minutes into the play that the
(intermittent?) stop issue ceases and the roll then plays correctly to
its end?

A discussion of the reroll brake and its operation starts on p. 49 of
the 1929 Ampico Service Manual, continuing on p. 52, and references
Fig. 27 on pp. 50 & 51.  In order for the reroll brake pneumatic to
"pull in" and provide a braking force on the take-up spool, three
different pallet valves, #1, 2 & 6 _must_ be closed at the same time.

Pallets #1 & 2 are operated by the so-called Pallet Control Lever
(p.  51) that drops into the groove of the take-up spool after the roll
has finished rewinding.  If the adjustments of Pallets #1 & 2 are so
grossly off as to allow them (both) to be closed during play, then the
intermittent closing of Pallet #6 by action of the rotating cam on the
electric roll drive motor will result in the issue, provided the answer
to Questions A & B above is "yes".  If the answer to Question B is "no"
and Question C is "yes", THEN Pallet #1 MAY be correctly adjusted while
Pallet #2 is mal-adjusted.

If the answer to Question B is "yes" and Question C is "no", I will
suggest a different problem: Examine the leather facings on Pallets #1
& 2.  It is possible that the glue which holds those leather strips to
their respective pallets has failed, and the even though the pallets
MAY be adjusted correctly, they are not pulling the leather strips with
them, causing the strips to remain covering their two holes each,
assisted by the vacuum on the tubes behind them.

Also check the condition of the leather facings of Pallets #3, 4, &5 on
the Reroll/Repeat pneumatic (p. 51) as a similar glue failure there may
contribute to the issue or cause other erratic behaviors.

If the answer to Question A is "no", and the issue presents randomly
and/or for irregular lengths of time, then the problem must be
elsewhere, for which I have no suggestions.  Good luck!

John Grant