[ Ref. Karl Juelg in 241009 MMDigest ]

Removing "back lead" will lighten the touchweight. The keys may be
too front heavy and so the leads were added. If the keys do not move
when a roll is played, I would look for binding at the key pins or
balance hole or, as Robbie suggested, at the key lock rail.

I often add back lead to older American consoles to raise the touch
weight, usually by 6 grams on the white keys (adding two leads to A0
and C8 due to their extra front weight).

Jon Page
Harwich Port, Massachusetts