I have the same problem with just one note: the same happened some years back - a single different note then - while my PX-330 was still under warranty, and so it got repaired under warranty, but of course, now it is no longer under warranty and we are stuck in semi-lockdown. so it's difficult to take the keyboard anywhere or get someone in to repair it! How would you suggest "blowing air"? On another thread it was suggested it should be compressed air. Would, for example, a hair dryer on cold, fastest setting do the trick? Or would it need the sort of pressure used for blowing up car tyres? Happy to try anything that might work without causing any further damage.