I can repair most any EM pinball that has not run in many years in about one to three hours, using this systematic approach. On the other hand, using the "fix just what's broken approach" usually takes me twice as long! (And I end up having to back-track and do the systematic approach anyway.)
I tend to agree with this approach from Clays Pinball Repair guide. The best way is to go thru the complete machine systematically. You may think it will take forever but once you start you get thru it rather than chasing your tail.
