Ok, I made it pretty far(so I think) without having to call on the experts, but alas here I am. It's column 5(grn-blk) and initially I found two disconnected diodes, repaired them and tested the rest, all good. Still no column switches so I check continuity from switches to connector 1J8 and then to first component past it, all good. There is a small inter connect board but the 1J8 wires go straight to pf. Then I check continuity between all components up to leg 5 on u40, all good. R77 tested good, so Then I check Q48 w/ diode test, red lead middle leg/blk outside legs and got the same results as surrounding transistors, 670 +/-. With options running out/along with my skill set, I wip out my latest lil tool, logic probe! Ok, now I'm testing the connector attached and the U40 legs while in game play mode, with my 3 and 4 player displays out this way seems easiest.. Connector results w strobe all Lo, cept for pin 5 which is Hi. All the corresponding output legs strobed Lo.
This is where the big dumb blank stare happens upon my face..., I figure I'm close but, I don't know.