When I got my Taito ICB years ago, I was fortunate to get it with a backup main board, which I sadly needed too soon... the game started blowing a fuse when you used one of the motors. With the other board in, the game is fine, so I don't think there is a fault with the motor at least. (It was a 6A fuse, would have been F1 or F2.)
The bad board has been put away for ages, but I would like to fix it. I'm not sure how to begin diagnosing the problem though. It looks like shorted BRs are implicated in some fuse issues on this game, maybe I should start there?
I thought about the motor drive transistors too, but don't transistors usually fail open? In my case, the fuse stays alive until the motor is in use.
Since it's been forever since this occurred, I can't recall if it happened when moving up, down, or both -- I will have to start over and take notes... but would love some ideas if you have any.