Many folks on this site will suggest that you get the batteries off of that board. remote battery pack, NVRAM or super cap. Lithium are better than alkaline.

Be careful messing around under the hood with the power on, you can get a good kick or worse yet short out some electronics.

I always buy a manual for my games, since I work on them but also for settings and part numbers and such. You can find it online and print your own but the quality may be lacking.

There are indeed great online resources. I like https://pinballrehab.com site too.