The bonus unit on this machine was not correctly stepping up and down. I serviced it as per the excellent Clay guides and replaced some worn parts (step up plunger and coil stop, reset pawl). The unit now steps perfectly, both in game and when operated by hand.
Problem is, the bonus is incremented one more step after it reaches 15,000. What's wrong here? Any part(s) missing? I looked at this issue for quite some time, searched the Internet for pictures/videos of similar units, tried adjusting the bakelite plate one rivet. Must be something obvious that I simply cannot see with my limited EM experience.
Attached pictures show the unit at the 15K position.
Is the limit on this stepper enforced solely by the missing tooth? If you look at one of the pictures, a pin in the "8 o'clock" ratchet hole (protruding through) would limit the unit to travel too far. So that might be missing. The credit unit on this machine has one of these installed.
Previous owner played the machine at home and probably had little experience with pinball machines. The bonus unit never worked as it should. The machine is located in The Netherlands. I can solder, have little experience with EMs, but learning every day. Hopefully someone can provide some insight or photos of a working Bally bonus unit of the same era. Thanks in advance.