One of the first things to check on an early solid-state Williams game with
weird, intermittent problems is the two bridge rectifiers mounted on the
rear wall of the backbox. The quick-disconnect connectors used to attach
the wires to the terminals are sometimes loose, causing playfield lamps to
go out, solenoids to be weak, fuses to blow, and other unpleasantness.
Tighten the connectors with pliers and reseat them once or twice to make a
good contact. Or, just solder the wires directly onto the terminals.