I have an old Williams em pinball I'm repairing that's currently stuck on ball 1 and never changes to ball 2. I've just about run out of ideas any starting point for me to check would help. The ball unit resets at the start of the game, but doesn't change afterwards. It's as if the coil itself isn't firing at all. I tried tracing it back but without a schematic it's difficult. It seems that the ball eject triggers the outhole relay which works fine, the outhole relays "opens in circuit to "on yellow" relay and closes in circuit to ball count unit s. U. Coil." does this coil directly fire the ball unit coil? I'm not sure what s.u. Coil stands for. Any help at all to get me started is appreciated.
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