Did you install a 6264 NVRAM? That is the most common one used on this WPC MPU board.

On a rare occasion, I see a 62256 installed which the jumper configuration would be different for that one.

Checking pin to adjacent pin all down the line on the NVRAM socket looking for a solder short is the next step.

@THE_PUMP_HOUSE, This sounds like the next step

With seemly no damage originally found, just apply 5v, 12v, and ground to the power connector to see if it boots on the bench or just plug in the power connector in the game. If it boots, it will save you all that time doing continuity testing.

The top 2nd and 3rd pins from the top right on your NVRAM socket may just have solder flux covering the traces close the pads, but they look like broken traces.

It also looks like you have all 4 pins in the picture with broken solder joints on the ROM socket.

Screenshot_20220718-115015 (resized).png

With the broken solder joints on the ROM socket, I would remove much of the old solder and resolder it. It is always best not to mix old solder with new solder. I don't think you need to completely remove the ROM socket.

How long ago were they bought? If recently, maybe Marco will exchange them. Worth asking.