There should be a switch on the 100,000 point relay with a grey-black and blue-white wire running to it. If it's gapped too close it could intermittently lock on the 100,000 point relay for all players. A quick test would be to put a piece of cardboard in between that switch's leaves and see if the chattering stops.
The 100,000 point relay is labeled "K" in this game, apparently, if you can't locate it easily.