LEDs flicker in controlled lamps on Bally and Stern SCR lamp boards

These lamp driver boards switch the controlled lamps with SCRs, which only stay latched on while enough current flows. A plain LED draws too little, so the lamps strobe or flicker. Fit a 470 ohm load resistor across the affected lamp sockets (often about half of them is enough), or use a plug-in load board that does the same at the lamp board. GI lamps aren't affected.