Ive had my DS for over 2 years now and the R button is starting to become unnresponsive, when I want to use it I have to push down on it hard to get it to work. The same thing happened to my SP a couple years after I got it and its R button stoped working entirely. If this happens to my DS is there any way to fix it?
Try opening it up and cleaning the contacts on the button. Just use some rubbing alcohol and a q-tip to clean up the copper on the board and that ceramic thing in the cloudy rubber piece. I remember having to do that every once in a while on my Genesis controllers a long time ago. Dirt and such would get between the button and the board and keep it from working properly.