Hello James:  The first thing to do is see if the hammers bobble
when you hand-play the notes.  Try getting the bobbling on both
soft volumes as well as loud volumes.  If the problem is there,
then it is probably just the piano action: it either needs regulation
or new buckskin to catch the butts at the bottom of the hammer shanks.

If the piano seems fine, check to see if there is any lost motion
between the player stack and the piano action.  One possibility,
although it is not too likely, is that the regulating button that
determines how far the pneumatic can collapse is set too low, so you
can't get a proper blow distance.

If you can't find any lost motion, then you may have to either re-do
the damper springs or just make the piano louder, which is an awful
way to "fix" the problem since the piano has no more subtlety to the
playing, and becomes a mechanical meat grinder.  Write back if you
have any more questions.

Regards, Randolph Herr
New York
aeolianpiano@gmail.com.geentroep [delete ".geentroep" to reply]