The first thing I do with any ss pin I get is pull out all of the boards for some "touch up" work. Almost 100% of the time there are cold solder joints on one or more of the connector pins, on one or more of the boards. As a means to keep everything reliable for the future, I reflow every connector pin from the solder side of the board, and find a means to clean and shine up the pins on the side the connector plugs into. I like the Dremel tool with one of these car wash wheel looking deals. Shines the pins right up and gets all of that oxidation and corrosion off of the pins to make a nice clean connection. You can use some types of erasers, some types of wire brushes, and other options to get the same results as well. The pins in the connectors can break sometimes too.
I also make it a point to remove any chips that are in sockets (carefully!) and clean the legs on the chips and reinstall them. The chip legs can become oxidized and corroded over time as well just like the connector pins on the circuit boards. On these old Bally and Stern games I make sure to check over the transistors on the circuit boards for cold solder joints as well. I've seen quite a few lights that won't light up even though the components test out good because of cold solder joints on the transistors. This goes for coils not firing as well.
Check all of your voltages on the power supply and make sure there are no cold solder joints on there as well. Power supply should get a new cap kit, and make sure the high voltage section is putting out good voltage so that your displays don't burn up. HV rebuild kits are available out there too if its putting out WAY to high of voltage. You can rebuild it and adjust the HV to let your displays last much longer.
Your displays can get cold solder joints on them as well, so make sure to clean those connector pins up and reflow them as well.
The rottendog and altek boards should be good.
I've got an Eight Ball Deluxe so if you need some wiring pictures if something looks funky there, let me know and I'll post what you need to see.