Hello, I have a Yamaha P-45 digital piano (6-7 years old), and I have been experiencing some glitchy behavior: namely, two keys (B1 and C#5) when pressed only make the note sound sometimes, and tend to stay silent especially when pressed lightly (but not always - occasionally even when pressed harder). I disassembled the piano and removed the two octaves to clean the keys and the contacts below (everything except the part below the silicon pads), but the problem still remains. Is there anything that can be done?