Check to see if the let-off rail support screws are tight and that the jack hits felt when it flies out from under the butt. Did you check for loose glue joints? Can the damper hit the spring rail? Could the hammer shank hit the spring rail? Can the wippen hit the bottom of the main action rail? Not likely but hey... Could the balance rail be slightly loose? Could one action support bolt be too low? Could the keybed support brace be loose? Could a caster be up in the air? Could the keys be ticking the key slip? Could the stickers be hitting the back of the keybed? Could the bridle wires be hitting backcheck wires? Could the spoons be ticking the damper lift rod? Hit the key and hold it depressed. Tap on the key, wippen from underneath, move the damper head back and move the butt back and forward. Try anything else to replicated the sound without using the key. Happy New Year and have fun. Newton
This PTG archive page provided courtesy of Moy Piano Service, LLC