This binding damper system is the most common problem I run into in my climate. Repinning seems to be the only fix. I have tried almost every magic potion I could find, and nothig frees them up. One place to check for problems is the guide rail bushings. You can ease and ease and they appear to be free, but the damper will still hang up. Often the damper wire is quite rough! One wonders whether the people making parts for these pianos have any idea what they are used for. Make sure the the wire is smooth and then put one drop of Protek on the wire just above the guide rail bushing. This seems to help. Have fun repinning. Things seem to go more accurately if you repin before applying the magic lubricants.
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