Quoted from AlexF:While I understand the suggestion to only adjust and fix what is broken, I think that mainly applies to newbies. It's a good stepping stone to learning how to go completely through a game. Which most 40-60 year old games are going to need in my opinion.
Generally if one stepper is gummed up and your initial problem, they all could benefit from a disassembly and cleaning. If one score reel is hanging up, they could probably all use some attention. The few games where I have only fixed what was broken usually resulted in chasing other problems later.
I can understand the idea of only fixing what is broken, but it's just not really a practical thing when you're bringing back to life a game that has been neglected for ages and is barely functioning. Is it working? Sure. Is it working to where it should be? Generally, not even close.
When I started the idea of taking one of these things apart was pretty daunting. The only way to learn is by diving in and doing it. I don't buy many games that are fully functioning, and even those that are, I generally do a lot of work on because they are not functioning to the level I want them to function at. And that involves taking them apart and cleaning them up.
If you just fix what is broken and leave the rest alone, on games this old, it won't be long before something else isn't functioning, and you're chasing problems constantly. Better to take them apart and get everything the way it should be than fixing one broken thing and declaring the game fixed, because it really isn't, and it probably won't be until you get in there and get into it much deeper.
Of course, if it's your first game, then you don't want to do it. And if someone has already done it, it's not necessary. But after you've done a few, it's much less scary and you'll learn a lot more digging in.
I'll make an exception on that for Grand Prix. That game still scares me after all the other games I've restored.