I've been following your progress and see that Chris H is on this thread but I wanted to mention something I saw in case it may help. Just another "Shot in the Dark" for you, playing Inspector Clouseau (my favorite late actor). I noticed that the CPU board in the first pic of your boards is a D20869 and came out of a "The Games" and your game is a "Touchdown" which would mean your board has been swapped out for some reason. I assume because the battery puked alkaline all over the original board. Anyway, it may be possible that your newer CPU board might require a 3K pull up resistor at the TC1 pins 7 & 11. Ed at GPE mentions this from time to time, sometimes the CPU board won't boot to attract mode without it. Perhaps it's worth looking into.

Steve
System 80, not just a job, it's an adventure

Okay, then that won't help. Switch matrix issues can sometimes be tricky (and though it rarely gets that far), it'll take out a gate in Z8 (7402), the input/output device selection. I'd give that gate a look over to be sure input/outputs are good, it may be what's locking it up.

Steve
System 80, not just a job, it's an adventure