I have an RD-300 that is around 20 years old or so and have a couple of intermittent/non-functioning keys. I'm have problems with Ab1, G4, and C#5. G4 seems to be the worst. Most of the time it doesn't work at all. This only started just recently. I purchased the keyboard in 2000 and as I recall, the previous owner (which happened to be a church) had the same problem with the G4 key but it had been repaired and was working perfectly until now.

I've opened it up to try and see what's inside. Interestingly enough, the case lifts up like a lid. The keybed can easily be removed by removing the mounting screws from the plywood bottom and removing the front rail. After that, you simply unplug the jumper cables and lift the keybed out. Beyond that, I'm not sure how to access the key contacts for the keys I'm having problems with.

Has anyone ever serviced one of these units before? If so, perhaps I could get some assistance on how to gain access to the key contacts.