The bonus stepper should go to the zero position and then step up to the 1000 position before the ball is kicked to he shooter lane. Have you looked at the bonus stepper?

While the score is resetting, the Bonus relay should reset the Bonus Reset solenonoid. The Reset relay will keep the motor running until the score and the Bonus stepper are reset.

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wrt where the relay is located ... easiest thing is look on the schem for the wire colors on the coil and find the relay with those wire colors.

note the score reel (drum unit) switches in the circuit howard highighted are different from the switches used to zero the reels. i.e. just because the reels zero ok doesn't mean the switches in the reset relay circuit are all open.

easy thing is stick a piece of paper between the bonus relay switch contacts in howards circuit and see if the reset relay unpowers when the reels reset (assuming the game over relay resets).