Holy crap...I’m about to throw this onto assembly off a cliff. Thank you all for the replies. Here’s where’s I’m at:
I replaced all of the original optos and confirmed those were working. All we’re registering except the 5th - it was really flakey. I confirmed it was due to the wire jumper because the solder pad was gone. If I held pressure on the solder joint with my finger, it was fine but as soon as I relieved pressure, it was flakey again.
My solution was to order replacement boards from Marco. I installed both yesterday and now only two optos register in edge test mode - 1 and 2. I can get them all to register if I place the boards literally touching optos to receivers but as soon as I put them in the bracket holder, only the first two register consistently. Not to mention the new receivers are taller than the old ones and are interfering with the mushroom buttons.
I’m kind of at a loss for where to go from here. I guess I’m trying to see if anyone else has had issues with the Marco boards. I should have just gone Great Lakes modular. Any other recommendations for an easy fix?