How to Troubleshoot a Bally Pinball Dot Matrix

Unplug the pinball machine's power cord from the outlet. Leave the pinball machine unplugged for a minimum of six hours or overnight so that the memory of the dot matrix circuit board can return to its default setting. Plug the power cord back in to reactivate the pinball machine's standby mode.

Unplug the Bally's power cord from the outlet. Remove the screws from the back panel with a Phillips screwdriver to expose the power cord. Pull the panel off the back. Grip the end of the cord and pull it out from the three-prong socket inside the compartment. Spray the prongs at the end of the cord with electrical cleaning spray. Reinsert the prongs into the socket. Place the panel back on, reattach the screws and plug the cord into the outlet.

Insert the key into the coin slot door. Rotate the key clockwise to undo the lock. Swing the coin slot door fully open. Moisten the edge of a soft cloth with lens-cleaning solution. Wipe the edge of the coin slot door that meets the frame with the moistened cloth. Spray the inside edge of the door frame of the coin slot door with a burst of electrical cleaning spray. Close the coin slot door and lock it in place.