I would start with a new rectifier board and also look for anything touching

Sometimes it fixes everything and if not you know you have a good power source and then easier to isolate and fix. I had a dead pin with just solid light on my mpu and only gi's and the rectifier fixed it. Always good to start at the source and then move on. Make sure nothing is touching under the playfield anywhere since you are blowing a fuse

It looks correct and yes you will have to solder about 12 or 15 wires to the board. Use small gauge solder to help. I also use some heat tape to hold in place and clip and re strip the wire and recrimp any burnt connectors.

Wow sorry I own some Ballys and none have rectifiers in the cab and just thought they would all be the same just different location. Well hell that's a lot easier. Sorry for bad information but still believe the rectifier and burnt pins are the place to start. I love this place and the information that gets shared.