Quoted from Pinsrgrt:I’d bet it’s the LED’s as I’ve had similar issues when switching over a Sys 11 game to LED’s
Yup! You need to do a small modification to the coils and AUX board to get the LED flashers working properly on System 11.
https://pinside.com/pinball/forum/topic/adding-led-flashers-to-system-11-games