Just finished a 1973 Gottlieb 2-player Jumping Jack play field swap out and got everything working, except one strange issue. The 2 upper kick-out holes when lit award 5000 points instead of the specified 3000 points. The inscription below the holes on the play field reads: "Lit hole scores 3000 points + lites 10x bonus. (The 10x bonus works fine.) I've never had the machine up and running until now, so I don't know how it behaved before the play field swap. I went through everything from top to bottom checking, repairing and tuning every relay, stepper, switch, gap, etc. that needed attention for the lower panel, back box and the new play field. The schematic is cryptic, in that, it doesn't depict how many points are scored for that function. My first guess is the "50/3000 score relay" holds a millisecond too long and pulses the score motor for an extra rotation. Also strange: the 5000 points is not consistent -- occasionally it yields 3000 or 4000. I'm stumped. There may be an easy explanation and solution, but I have no idea where to look. (I assume this would also apply to 4-player Jack in the Box machines as well.)

Any advice, ideas or clues w most welcome. I'd happily post more pics, but I don't know what to show!

JJ 3000 pts (resized).JPG

Smooth rhythm. 1-2-3-4-5

Rolf: Brilliant! I am in awe of your genius. That 4B switch is the most invisible one on the score motor, which is why I probably missed it when I serviced all the switches. It was, as you suspected, maladjusted -- closed tighter than a flea's butt. Easy fix, and it works! 3000 every time. If you had not proposed this solution, I wouldn't have found it for weeks, maybe months. I see the logic now that you pointed it out. Thanks!!