Working on a Target Alpha and have a strange problem with the match unit (0-9 unit). This is one of the mini steppers tied to the 100 point (M) relay. After getting it moving (it wasn't firing at all), I noticed that the alternating relay wasn't changing so the lights on the playfield were not switching side to side. The match unit was firing and turning so I was stumped. As I've investigated further, I noticed that when I move the match relay by hand, it moved properly, stepping up one at a time and the alternating relay works fine. But when the match unit is fired by the M relay, it always steps up by two. The causes the alternating relay to not move as the switch is still in the same position. No matter how hard, light, fast or slow I manually move the match unit, it will move up by one. But it is moving by two when the M relay fires it. I can't replicate by hand.

I hope I'm explaining this well. I'm guessing something is misadjusted, but I just can't seem to figure why the arm is pulling back far enough for two clicks when I can't do it by hand. Anyone have any ideas or experienced anything similar?

Thanks so much.

Thanks as always @howardR. This detailed info is exactly what I was looking for and couldn't find.