Just a warning, I am no tech., and new to pinball!

Hi everyone,
I recently came into a Laser War machine!
It seems to play well now with a little tweaking. There is only one major problem - the sounds are out of order and the talking comes on randomly (out of step with play) throughout the game.
For example, it always says "Last ball!" on every ball, and it will say "return to yellow base...return to blue base", etc." randomly throughout the game even when it is not part of what is happening. In fact, the talking is almost always happening, there is very little "just music" throughout the game?
Any thoughts of what that could be? FYI, the boards inside are blue, not green like some of them, if that helps.
I am not a tech in any sense of the word, but the game is not enjoyable to play right now, especially as I am trying to learn it and it is giving me false instructions!!
It appears an owner at some point did some repairs/mods (e.g. the battery) at some point. I can take pictures if that helps.
Thoughts?
Thanks!