Hi all,  I recently asked for advice on a restored Autopiano which
performed poorly upon completion.  Firstly many thanks to those who
responded to my cry for help.  Secondly, I should have said it is a
single valve action.  Briefly, these are my findings.  Where
appropriate related to the specific suggestions made:

Andy Taylor, Bernt W. Damm, Richard Vance, Sam Harris and John Tuttle
all gave practical methods of determining the pouch to valve clearance
and testing for wind motor operation.  They included:

1.  Measurement of differential between pouch dish and valve stem
protrusion,

2.  Insertion of temporary spacers between the pouch board screws
and valve chest,

3.  Placement of small shims on top of the pouch.

Regards #1 -- I had read that 1/8" was the overlap for the valve stem
button  above the gasketed edge of the valve chest.  This is what I
initially set them to because I was under the (false) impression that
the pouch was "sucked in" during pumping until such time as it was
played.  I now know that it remains more or less static in its dished
position.  When I measured the pouch dish it varied from 1/16 to 3/32.
1/16 minus 1/8 equals a clearance of minus 1/16!  QED.

Regards #2 -- I did not try this method although it sounds perfectly
feasible.

Regards #3 -- I followed this method very carefully -- what an
eye-opener!

Firstly I glued together 3 small cardboard key-rail washers such that
their combined thickness was exactly 5/64.  I turned the pouch board on
its back and placed the shim on a pouch to test.  I then lowered the
assembled valve chest over the board slowly until it mated.  During
this process I watched the end of the wire stem of the valve for
movement.  Initially it moved a lot!  With adjustment I was able to set
it so that it just flickered.  I knew then that I was very close to
1/16.  I tested it this way on a few others and then compared the
height of the valve buttons.  They were all the same.  I therefore set
the whole board to this height and reassembled.  Thank you John Tuttle.

This now takes me into the area of testing.

I am grateful to Doug Rhodes for his warnings on misleading results
from household vacuums.  I therefore decided to set up a test rig using
a spare lower action and connect just one suction pipe from the main
bellows.  This gave much more realistic results although its hard to
see round the back of an action when you are pumping at the front and
pricking the masking tape over the tracker bar!  A mirror is one
answer, of course.  Feeling a lot more confident I reinstalled.  It was
good.  Roll alignment was an area of regulation that took up a lot of
effort but I got things running OK.

Moving on to the wind motor problem, I could not work this one out
initially.

I had already adjusted the two variable items -- the spring strength
and stop button -- but no go.  Then I took the governor apart again.
Although all of the inside components were in good order (I had checked
them for wear, etc.) I noticed that the 10" wire that operates the
sliding wooden valve (shaped like an old wooden clothes peg) was kinked
at the screw connection end.  Not hugely, but enough to turn the valve
at the business end to an angle that left some of the wind motor
suction hole exposed in a rather unpredictable manner.  I kicked myself
for not spotting it earlier.

With this corrected the wind motor worked beautifully.

I now have a working instrument and a lot more experience.  Thank you
to all contributors.  It just confirms what we all know to be true --
MMD is great!

Yours gratefully,

Roger Waring