Hello:  Can any one tell me the purpose of the light spring acting
on the slow crescendo pouch of the Ampico A?  It can be seen in the
1923 Inspector's Reference Book Illustration 2 Item 19.

I am relatively inexperienced in the Ampico A mechanism and am just
now completing work on my second instrument and found the spring was
missing in one of the crescendo devices.  It was presumably lost or
removed by a previous rebuilder.  Since I did not have any suitable
wire to make a replacement, this unit was rebuilt without the spring.
Bench testing revealed no problems and it seems to be functioning
perfectly in the piano.

Should I be looking for a suitable replacement spring?

Regards
John Johns
Ottawa, Canada