Helllo,
I have had my Roland RD-700NX for well over 10 years now. In the last month 4 of the keys have become silent.
It started with one, the went to the one next to it and then the two black notes next to those.
What can be done to fix this?
It’s worth tearing down the keyboard to check the PCB under the keys.
Clean them and the rubber contacts. Check for any corrosion on the components.