Greetings, I recently tried to clean a pair of right joycons. After that, one of the joycons’ Plus/Start button stopped working and the other one ended up with a faulty A and B buttons. Any suggestions for what can it be?
Hmm, that’s an odd one, as they are on the board itself and you have only been cleaning it cant be anything like dodgy ribbon cables. It could just be a case of the rubber being out of place slightly, or maybe something get under the clicky metal contacts. Did you open it to clean it, or just from the outside, and what did you use to clean it?
I would take it apart again, and see if they work when it is disassembled and you press the buttons directly.
I opened and cleaned the boards with isopropyl alcohol and compressed air, didn’t use that much, just to be sure something like dust was laying there. They worked before cleaning, however after the procedure the buttons started to fail.
I would be tempted to open it up again, and test it with just the battery and aerial connected. If it isn’t working like that, you could peel back the sticky film with the metal contacts on that’s over the face buttons (carefully!) and clean under them.