My LW3 is fixed and working now. I want to document here for others:
The original problem was on the low voltage circuit.
Low voltage circuit on PS board: I (probably mistakenly) replaced the power transistor and (probably mistakenly) replaced the voltage regulator chip. I was able to socket the chip while it was out of the board. That didn't fix things, so I bought a Cap kit and replaced 13 electrolytic capacitors. I did see where a capacitor had apparently leaked onto the board. The leak spot was subtle, but there and was largely hidden directly under the faulty capacitor. Installing the 13 capacitors seemed to fix the low voltage side, and everything on the machine worked except the display.
High voltage circuit on PS board: In the course of handling the board while doing low voltage repairs, the fuse clip holding fuse F7 on the high voltage side must've been knocked ever-so-slightly loose. Either the clip was knocked loose or the fuse clip pins had slightly spread and were not making good contact with the fuse. I bent the clip pins in slightly with my hands and gently jostled the clip on the board. Suddenly, voltages appeared on the high voltage output pins. I put the PS board back into LW3 machine and voila! - everything worked.
As a note, pin 7 on CN1 is part of the High Voltage circuit. The way it's depicted on the manual's PS schematic is not clear to this amateur. An EE at my work told me that it originates from the center tap on the transformer and is the AC ground reference point. To be clear, pin 7 is ground and is a part of this circuit.
As an additional note, when measuring the connectivity of the fuse F7, if possible one should measure from the BACK side of the board where the traces are. This also checks that there are good connections from the front of the board, through the board, and onto the back side.
Wife and I had a fun night of LW3 pinball!
When I get time, money, and most-of-all renewed energy, I'd like to enhance the machine like somebody on this forum has.
Thanks for all your inputs!