Bird, bird, bird, bird is the word. Sorry, 'bout that, but every time I see your name that pops in my head. Check out my favorite site.
http://www.marvin3m.com/fix.htm Look at the 1930 - 1978 E.M. repair guide. Very good stuff!! It is a bit overwhelming if you have no electrical background, but there is a ton of information there for you. Section 1E explains switches, relays, steppers, etc.
I have restored a few EM games and 99 % of the problems were that the steppers were gummed up. This causes major malfunctions. The other problems would be that a switch is not closing when it should because the contacts are slightly bent and therefore not making contact either in a Normally closed or an energized Normally open contact(becoming closed while energized). Pinball resource sells a switch adjusting tool. It's cheap and effective. But avoid bending the stiff staionary contact. Bend the one that's suppose to move.
Hope this helps.
Larry.
