What kind of things can it cause. Nothing has been done to this machine and it run so amazingly well. I just need to figure out what i want to do about the fast pac. It is absolutely crazy. I have never played fast pac where everything is sped up. The ghosts, sounds, timers, all are crazy fast.
"The game came from the factory with a filter card between the wiring harness and the main game board. This board was installed in order to pass the FCC's RF Interference requirements. Without the filter board installed, the Radio Frequencies produced on the game board would sneak back down the line cord, causing all of the AM radios in the area to 'buzz'. Since this is no longer a problem, we recommend that if it hasn't already been removed, you toss the filter board over your shoulder and make a wish.
The filter board is not necessary and just adds one more set of contacts for our four power wires to pass through."
http://www.twobits.com/Humbar/