World Football pro uses a series of boards that communicate via RJ45 cables to control the game. When the rear display controllers are not receiving any data they display the message "no com". The message will be displayed on the lower scrolling display when the lower board has no communication or in between the time and goal sections if the upper board is not receiving communication.
Connection points for the communication lines are located inside the left and right podiums, in between the podiums and the floor of the game and in the upper access door in the rear of the game as shown below, the network jacks on each board are in parallel so it does not matter which jack is connected on the boards.
To trouble shoot the NO com error first start by checking that all connections are secure and the dip switches on all boards are in the correct position (See the system diagram for the proper settings).
Unplug all network cables from the main board, then using a different network cable connect one end to the main board and run the other end to the rear of the game and plug it into the either of the display controllers.
If when the cable is plugged into the controller the displays show data then there is a bad network cable or connection in the game causing the display controller board to not receive its data, isolate the bad section of cable and replace.
If the display controller shows no data then move the network cable to the other display controller, if there is still no data then check for power at the main board connector P11 and if present replace the main board. If the display shows data then then replace the first display controller you plugged the cable into and check the network cables between the display controllers.