This is my little advice. Billc is spot on. Score reels, Stepper units and BX and AX relays! boy there touchy. You will meet some people that know their stuff. take LOTS of pictures before you remove things. You might think about getting a Gottlieb catalog for your machine from The Pinball Resource. If you need new parts Steve really likes part numbers. Take your time, No WD40 ever. It is truly a great (and sometimes very frustrating) Hobby.
Following,,,
Mike.