I’m trying to get a Gigi to light a (any) match lamp consistently at game over. Right now that’s only happening about two thirds of the time. The other third of the time the switch contacts on the 0-9 stepper aren’t lining up, and therefore no match lamp is lighting.

I’ve made what I think are the usual adjustments, including:
• Removing, cleaning, and adjusted the positioning of the coil
• Checked the various spring tensions
• Checked the bracket that limits the movement of the coil plunger into the coil
• Checked the bracket that limits the travel of the arm that rings the bell

When manually activating the coil, I noticed that the arm that “pushes” the gear up and advances the stepper wasn’t always pulling in far enough to push under and up on a gear tooth. So I was pretty sure adjusting that spring tension tighter, so that the arm always retracted under a gear tooth, would fix the problem. Wrong! The stepper is still occasionally missing a contact.

Any suggestions for the likely cause or other adjustments I can make?

Thanks in advance!

Thanks Tim for your detailed suggestions. The set screw holding the spider to the axle is tight (on this Gigi there is only one screw). I've tried sliding the coil case back and forward to adjust the amount of drive arm travel, as well as the limiting bracket next to the coil. No adjustment so far has made any noticeable change. The coil stop itself is also tight. I'm wondering now if it's possible that the problem is caused by the stepper being turned "too far", like 1-1/2 the desired distance rather than 1/2?

Let me know if you have any other thoughts. In the meantime, maybe I'll get lucky and find the right combination of adjustments that will make it light the match lamps consistently. Thanks again!

At the risk of jinxing myself, I think this issue is now fixed. As I started to suspect, it turns out the stepper was being advanced too far rather than not far enough. I didn't confirm that until I actually watched the stepper advance during play and could see that sometimes the stepper would advance as far as two and a half rivets. So although I ended up trying a lot of adjustments, I think what did it was adjusting the bracket between the coil and sprocket to limit the travel of the plunger, as well as adjusting the bracket that limits the travel of the arm in the opposite direction (in the upper left of the picture). Those adjustments eventually limited the stepper advance to the distance between rivets - no more and no less. After getting that right, I noticed that the rivets and spring loaded "fingers" weren't quite centered. That was fixed by loosening the three screws that hold down the outside bakelite disc and rotating it slightly. I've ended about fifteen games in a row with a match lamp lighting each time, so keep your fingers crossed.

Thanks for all the help!

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