Well, I've been banging my head on this one for a couple of days now. Long story short, I have got everything working (in theory). GLM three opto board recognizes all open/close positions of the three optos. However, switch test does not acknowledge the activity. Swapped cpu's and the problem doesn't change. Can someone more fluent in schematics explain to me what I am chasing? I guess more specifically, how does the opto board communicate with the brains of the machine?

Excellent! The test failed initially, but I had not done the test since reworking everything. I was testing manually in the switch test. Test passed! Thank you both for taking the time to respond

And a plug for pinball rebel. I use the site from time to time, but I did not know he had the tech charts for a ton of games listed for a quick and easy reference