I can possibly help you.
The first thing I do is to take the steppers and score reels apart and clean them?
Do you know anything about switch positions like normally open (no), normally closed (nc), etc.? You will have to check them to make sure they are doing what they are designed for.
Do you have an electrical meter? Rarely you may have a bad coil or motor. You may have to check them.
Usually, these things are gunked up with old hardened oil. Cleaning is the first step. Tons of fun.
After everything is moving like it should and stuff is not working, then you have to troubleshoot. Can you read a schematic?
Larry
Here's a video I made awhile back. Just shows a score reel sticking because of old grease.
https://www.youtube.com/watch?v=1uK9laNEC8U