For those of you that have noticed your keys making more noise than when new, I may have a solution. My F4 has started to make enough noise that I hear it during play. So, today I took my keyboard apart and could not see anything making the sound. Then I tried a spare key and found it made more noise! After some thought, the only difference between keys was the new one did not have grease on it. With that I applied more grease to the old key and problem solved. It was the rubber bumper on the key that connects to the weighted arm with sensor. I will be greasing my keys. Just a small amount. Let me add this does not cure noise heard from felt pad.