Andy Taylor probably does not have his pouches sealed tight enough.  Old
Coinolas used rubber pouches however Seeburg, Cremona, and others used
leather as did later Coinolas.  North Tonawanda pianos (Capital) used a
standard action stack without problems but then the spool box was located
on top of the stack.  Try connecting only the piano stack and spool frame
before adding any other extra instruments.  I still use rubber cement to
seal pouches as no matter what anyone tells me, silicone is a mess.

Check your valve travel.

Don Teach

Shreveport Music Co
1610 E. Bert Kouns
Shreveport,  LA  71105
dat-smc@juno.com