Maybe need a new board. We had some of the first minis, and played in all kinds of weather. We then played Campaign, the year Rheanna had that umbrella number 1 single, the year we had a monsoon at Campaign.
We got water in the gun, and most boards were fried.
I believe they coat their boards with something these days making them more resistant to water. Might need a new board mate.
Could try taking everything apart and putting it in the airing cupboard, or a bowl of uncooked rice. Try dry it all out a few days and try again?