One of the main issues with my Sky Jump is with the ball count unit: it's not always stepping correctly to the next ball. As well, even if it does step to the next ball, often the backglass bulb for that ball does not light up unless I press on the back so the wiper makes better contact.
During this thread I will share my path through complete disassembly and rebuild of this unit. This will be the first time for me but in the end I hope to have a fully working ball count unit, but most importantly, I hope to be more comfortable with these types of stepper units in the future. There is no substitute for experience so the only way forward is just for me to do it and hopefully learn something along the way!
Of course, as always, your comments and suggestions are greatly appreciated!
Now, what little I know about steppers I have read from the very important website:
which goes over the different kinds of steppers and how to fix them across the major manufacturers. I will be following advice from here so I want to say thanks in advance to those responsible for producing this great website.
This 1974 Gottlieb Sky Jump ball count stepper is of the Step-up/reset type which means one coil steps-up one by one and the other coil resets it all the way to the beginning. It is important to note also that very similar assemblies can be used for many different purposes so in the 1978 Parts Catalog (Volume P), you will find similar looking assemblies but not exactly the same as the ball count unit. In any case, this thread may be applicable to other stepper rebuilds like player units, coin units etc.
Here are some pics of the ball count unit in the lower-right corner of the backbox:
Another site worth mentioning: