As a Yamaha warranty and service centre we have a reasonable number of enquiries for P series, CLP and clavinova Electric pianos whos keys around the middle section have stuck down, or are slow to return when pressed.
We have found that keys around the middle C get the most use and are therefore subjected to more wear. It is generally only the white keys which have issues.
Fortunately we have identified the large majority of the causes of sticky or slow returning keys on Yamaha Pianos. The fault lies in the hinge mechanism of the key. Over time the plastic becomes brittle and eventually the hinge pivot point will crack or snap. While it still holds the key in place, it creates a stepped feeling when pressed. On the return the key often gets stuck a few mm below the other keys, or returns but is more sluggish to do so.
We stock several of most Yamaha keys in the Clavinova, P and CLP series and have them ready to fit on the shelf. We can either supply you with the keys if your DIY inclined, or you can bring your piano to our workshop and we can replace them for you and check all the other keys while we’re there. We have developed a technique to test all other keys and find the fault in other keys which have not yet fully developed the fully sticking failure fault yet to ensure we can change all faulty, and on the verge of becoming faulty. Often it will only be 5/6 keys which will ever go wrong and fail.