Just as I was done shopping my Cue Ball Wizard and going to enjoy a nice 100% game when I noticed lamps were out, darnit. The whole last column (9) in the lamp matrix. I swapped all the bulbs and buzzed all the lamps in the chain and they seem to be good. I DMM'd the diodes and they seemed to check out okay too. Transistor Q52 checks okay.

What am I missing? Should I try reflowing all the solder in the chain?

Fixed.

I kept looking until I noticed that the entire column was NOT all off. One light (Ball #7) still worked in the column that I overlooked in the schematics. f***. I traced the wires in that area and found a broken wire at the back-left of the playfield, cut by the left playfield hinge when moving the playfield around.

Game on!