If your machine's lights dim when a solenoid fires, such as the flippers,
then you probably have a connector problem on your light circuit. This is
most common on solid state machines, usually Bally. Check the main
connectors on the power supply. If the terminals are corroded or scorched
then this could be your problem. Check also that the terminal pins mounted
on the board do not have cracks in the solder. If so, reflow the
If you have an electromechanical with this problem then it could be the fuse
block, or even the tilt switch contacts.