Gorgar has been brought back to life! Rebuilt original boards, cleaned, new rubber, bulbs, all adjustments, and new aesthetics. After solving multiple overlapping problems, I'm left with one single issue. The "3" switch is dead. The manual shows it on the switch matrix and all switches on each side of it function. The DMM says it's closing and trace voltage mirrors adjoining switches. Is it possible that the driver or MPU have a bad component? Because the wires look good and I resoldered the one joint that looked weak. I even tried directly shorting the switch to see if it was some weird contact issue. Nothing. I've read up on pinball switches and other supporting articles I found but I'm not sure where to go from here. Any help would be appreciated. I'm thinking the next diagnostic I'll try is to bypass the actual wires with alligator clips to the previous switch in the chain to check for a possible voltage drop I'm not seeing.

I may have found the culprit. I see there is an outage wire here that one other target does not have. And the diagram shows the Green/yellow being attached yet it isn't. Looks like a hack of some sort. Can anyone chime in and say if it's supposed to be like that? I could just split the feed from the previous switch and add a jumper between them. But I don't want to short out my board so I need to figure out if that's the right thing to do.

IMG_20210428_091311 (resized).jpg

IMG_20210428_091320 (resized).jpg

IMG_20210428_091332 (resized).jpg

This is the dead switch without the Green/Yellow that the diagram says it should have.

IMG_20210428_091306 (resized).jpg

Solved
I was probing around with my DMM and everything looked right. Trace voltage, diode, switch closed resistance, everything. On probing around I accidently scored a point. Then I tried to recreate it and found that the contact plate had been reassembled in the wrong order and was insulated from the switch contact. Bam, found it. Drilled it out, resequenced the plates, riveted together, tested and all set to play.