Your game couldn't have worked with the way the J2 connector at the rectifier board is wired.
The yellow wire (AC line power) at pin 4 should be at pin 6.

Oh dear...

Is fuse F6 on the rectifier board still good?
Are you getting 115VAC at the transformer?

The Bally rectifier board schematic lists pin 4 at connector J2 as "SPARE".
I'm looking at a Bally rectifier board right now and pin 4 is not connected to anything on the PCB - it is in fact spare.

Rectifier_Board_J2.png

Now, we come to the wiring diagram in the schematics and pin 4 is listed as "SPARE GRND" (as in spare ground).
I can't see how your game worked with the yellow wire there since pin 6 is where power goes to the transformer.

If X-Pin wired pin 4 on their rectifier board to ground, then you potentially should have been blowing/tripping the house fuse immediately on power-up because your active (hot) wire was connected to ground. Only way the fuse would not have blown is if your game has active and neutral reversed - I've come across a number of early Ballys and Sterns that were wired wrong from factory with the games main line F6 fuse being on the neutral side which is incorrect. The mistake usually being at the wiring of the EMI filter in the lower cabinet.

That yellow wire must go into pin 6. You also need to make sure the line active prong on your cord reaches the main line F6 fuse via pin 6 of J2 and the power line neutral prong reaches pin 7 of J2.

Rectifier_Board_J2w.png

Here we see that the yellow wire goes to pin 6 of the J2 connector at the rectifier board:

Cabinet_Power.png

Why do you want to bypass the power switch when you said a few times early in the thread that the rectifier board downstream was getting 120V ?

It might also be an idea to post clear photos of your:
- power cord plug
- top and bottom of the EMI filter showing how it's wired
- pictures of the rectifier board showing the right side where the power wires go to the transformer
- with the cage around the transformer removed, a front photo showing how the transformer is wired
- overall picture showing all the open backbox
- cabling on the lower right backbox area (showing cabling from the cabinet to the rectifier board)

Can you tell us exactly how you're measuring power? - i.e. how are you setting the multi-meter and where exactly are you putting both meter probes when you're measuring at the rectifier board?

Then we might have a better overall picture of what's going on.

I can see the bottom of the EMI filter is wired backwards based on wire colors. If the wires on top are backwards too then two wrongs will make a right.