I reciently received my Novation Xiosynth from storage. Needless to say it collected some dust. I used a damp towel to wipe off all dust from the surface and proceeded to use compressed air to blow out any from between the keys. All keys do register a signal, except a couple only register at 100% velocity no matter how gently i press the notes. There shouldn't be any condensation on contacts since it's been over a week since I wiped things off. Any ideas?