Hi folks. Having problems with a Williams Space Mission bonus unit. At end of ball, the bonus unit counts down properly to zero, then resets to 1,000. However, no points are awarded for the 1,000 position. So if there is 10,000 on the bonus, only 9,000 are awarded. If the bonus is at 1,000, no points are awarded. When the bonus is over 10,000, either 1,000 or 2,000 points are deducted from what should be scored. But, if on double bonus, all points award properly; no points are deducted. After the bonus downcount/reset, the next ball or next player starts correctly.

The bonus stepper appears to be operating properly. Step-up and step-down move cleanly. The contact points are cleaned and lightly lubed. From what I can see, the wipers appear to be in the correct positions at 1,000.

Any help/suggestions what to look for greatly appreciated.

Thanks. I checked the open at '0' switches, and they both open properly at '0'. I looked at the switch stack on the score motor impulse cam, and it appeared the C switch needed adjustment. Afterwards, it properly awards 1000 at the 1000 position, but then for higher bonuses awards too many 1000s. More adjustment required.