I am a Nip It lover and trying to clean and tune it up my machine. It plays well except for no 1000 bonus default on start. I am curious about one thing,,,I notice a bulb socket under the playfield inside the cabinet. I put a bulb in but it doesn't work. First off, what is the purpose of this light socket inside the cabinet? Is it supposed to be there and if so, any ideas why mine does not work? I tried numerous bulbs but no luck.