That in itself on this game is no easy straightforward task. The roller sizes are not compatible with typical Atari trackball sizes. Don't know if he replaced the rollers, but if he did, he likely had to have them custom made (unless he bought them from when Jeff @ chips4sle remade them). And just removing the trackball to clean it is, if I recall correctly, 37 screws/bolts, with like 6 different size wrenches involved. What a pain.
Awesome game. I don't think I could sell mine anymore. It's just that unique and fun to own. I wish the repro art for it would get finished, but oh well.