There's some good advice in EMsInKC 's post but when it comes to "get into all the steppers", and (at the risk of misunderstanding his advice about) "adjust a lot", sorry but I have to disagree. This forum is filled with posts from beginners who tried wholesale, shotgun repairs, and in doing that caused more problems than they were trying to solve.

What to do: Take one problem at a time, slowly & carefully understand its cause, and only then fix just that. Much later when you understand what you're doing if you want to overhaul (for example) a machine's steppers, go right ahead. But that time isn't now.

To do that, you're going to need to know how to read the schematic. Read currieddog 's post #4, above. We can help you.