Sorry to bother you folks again but I'm trying to solve a problem with my Skylab pinball machine and I heard it had to do with the Advance unit which lights up the letters in the word Spacelab as your score advances. I'm assuming it's one of the stepper style units. There's 1 mounted to the underside of the playfield and 2 located in the backbox. I'm not sure how to adjust it but first I need to know what I'm looking for and go from there. Any help would sure be appreciated.

Thanks so much. Now I just need to figure out how to make the adjustment needed to repair it