I bought a yamaha dgx 660 about 2 years ago. Noticing today that I can hear a springy sound after hitting one of the keys, but I'm pretty sure I've noticed it for a bit and didn't think much of it at the time. Any clue what this might be down to? Is there a way to clean that area incase something got in there (solid or dried liquid), should I go to the seller or bring it in to a repair shop? I've been getting pretty into learning and this is such an annoying setback now that I'm starting to make progress. Any opinions would be appreciated!