One problem not mentioned is that the action, stack, keyframe, whatever is taller than it should be. This can be caused by a glide bolt run down too far, a stack mounting block unglued, drop screws too high, fallen block warped case or plate screw extending through the bottom of the block. Get down there with a flashlight and _look_ and see what is happening, including removing one or both leg screws (and hope someone doesn't lean on the piano too hard or play the notes real hard. :) Newton
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