Changing the switches around fixed mime for awhile only: the uncontrolled pressing of the switch by kids flexes the board and does all kinds of havoc on the multiple connections.
Using a very thin tipped soldering iron, I remelted a lot of the contacts all over the board (using my best reading glasses) and even added a bit of lead in a couple of places that seemed thin. Flawless for a couple of months now. I had nothing to lose, saved me from buying a new board.