Hi Chris,
Before you go to the expense of a repair, check your Foot Controller setup. When I first had my FC I was always 'nudging' the first pedal which, obviously, the keyboard was quick to react to. To avoid this, I set pedal 1 to "Fill-in 2" so if this happened, no one would notice as the keyboard just gave me a 'fill-in'. I then set the rest of the pedals as required then using the CUSTOMIZE button, pressed 'DATA CONTROL' and switched the Foot Controller to "ON" It worked, and was fine until I loaned my keyboard to someone else who obviously used his own setups and when I got it back I was unaware that he had changed my setups, so I was back to 'square one'. However, it took me some time and several embarrassing moments to realise what had happened when of course, I quickly remedied the situation.
The point you have to remember is that if the DATA CONTROL isn't switch to "ON" then whenever a floppy or an SD Card is loaded, the keyboard will log the latest settings and will react accordingly. So I would suggest you check all your settings in this area first, it could save you a lot of money.
Hope you understand all this if not email me privately and we'll go on from there. Good luck!
Aud (U.K.)