I have a Roland D5, which I use as a slave keyboard, and half a dozen of the keys (all adjacent) have stopped working. My computer tells me that there is no MIDI message coming from them, but the sound generation unit is still working for those notes. I've had it apart and it looks a bit gungy in there (and difficult to pull the keys apart!). Can anybody tell me if it is likley that the fault is mechanical or electrical, and has anyone else had this problem and fixed it ? Cheers. Andy.