Hello, I picked up my first EM last weekend, a 1975 Gottlieb Top Score. The game seems to be in pretty good shape, with two issues, although I think they are related:
1. The spinner works and scores, but the yellow lights do not advance with each spin as they should.
2. The bonus lights down the right hand side of the play field do not alternate. The same ones stay lit at all times.
If I take off the glass and spin the spinner by hand, the yellow lights occasionally advance, and the bonus lights will alternate, but not consistently.
I read through the very informative guide by Steve Fury (https://pinside.com/pinball/forum/topic/em-pinball-circuits-basics-to-not-so-basic), and I also have the schematic from Gottlieb. The previous owner said that he repairs pinball machines (and might very well be a pinside member for all I know). The game is in great shape overall, and it looks like he took good care of it.
Based on my very limited understanding of EM machines, I think that both of these problems are related to the Alternating Relay (A on the schematic). I watched the relay while spinning the spinner, and it moves but not much.
So I guess my question is this: now that I know what the problem is (or at least I think I do), how do I fix it? Steve Fury's guide was very helpful in understanding how things work, but it didn't really explain how to fix a broken relay, or how to clean one that is only slightly working. Is there a basic guide on here for how to do EM maintenance? I searched for other posts with similar issues, but most of them assume a level of knowledge above mine. Thanks in advance for the help.