This occurs because the key or pneumatic has not pushed the wippen
through sufficient travel for the jack to clear the hammer butt.  First
check distance of hammer from string; depending on the manufacturer:

    spinets - 1 5/8"; uprights - 1 3/4 to 2".

Take up lost motion with the capstan screw.  Level and set the dip on the
keys. Dip is usually 3/8 inch.  Adjust backchecks, letoff and dampers.
Check hammer springs for sufficient tension.  Are the bridle straps torn?

Adjust player pneumatics to wippens.  Adjust pneumatics stop rail to allow
equal travel of wippen as key dip.

If one tech has not done this properly, call him back to get it right
or get another.

Jon Page¶
Cape Cod. Mass¶
jpage@capecod.net