[pianotech] Young Chang action noise

[Jon Page]

If it is not the knuckle or jack rest felt; it is the back rail cloth.
If the back edge of the felt is glued to the rail, it will be a point
of hard impact. Cutting it loose might be enough to abate the
noise. If you get into installing under felt, you will be affecting
action elevations and damper timing and maybe touchweight
will be affected.
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Regards,

Jon Page