Hi Dave,
Given that the fuse is lasting 20 games or so, it could be that the fuse is getting stressed every game, but not enough to blow until it finally breaks down. Does the fuse look a bit shitty after 10 or so games? If so I wonder if an amp meter in series with fuse (analog would be best), which could be in view while playing, would show up at what stage during game that the amps peak? Just a thought..
Cheers
Dave