Ok, I am missing something on this one. I am finishing up a playfield swap on a TAF and column 3 of the switches are dead. They do nothing in the switch test, I cannot trigger them with jumpers and a Diode, and I seem to have continuity all the way through the switch circuit. So I assume U20 is dead, right?
I bought a bunch of the chips a while back and have put no less than 5 in, with none of them bringing the switch column back to life. So surely I do not have a bag full of U20's that are all dead in the exact same way, Right? What am I missing here? The MPU is a new aftermarket unit from Rottendog.