My basic rule is “If it ain’t broke...”.

It’s your first machine and sounds like it works. Don’t start with the boards. There is nothing indicating a power or light board problem so don’t waste time and money on them yet.

Start with something simple that will improve game play.

First- clean it. Strip down the play field clean and wax. You’ll learn a lot about the mechs just by doing this clean the plastics replace rubbers.

You’ll also se if there are problem drops or other parts by doing this.

First real refresh should be your flippers. By a rebuild kit and go at it. If that is successful then you can decide if you want to refresh the drips slings or pops next.

Just don’t try to fix everything at once your first time. Fix one thing and play it a while. Then go to the next.

Maybe on your second machine you can do more at a time.

Good luck.