Milk jug toss uses a thermal sensor to detect people reaching too far or climbing in to the game, when this occurs the game is ended and the display will show 7IL7 ( TILT). When properly installed the sensor should be pointing at the jug if it is off to the side or tilted down the sensor will pick up false triggers. The sensor input on the main board is located at the J7 connection. To determine if the sensor is operational you can check for the signal line (grey wire) referenced to ground (black wire), when the sensor is open you will see 0vdc and when the sensor is blocked you will see 5vdc . The sensor must be connected for the main board to go into game mode. To bypass the sensor you can short the grey and black wires in the J7 connector together, if this works it tells you the sensor or the wiring is causing the fault.