There’s a 25K trimmer potentiometer on the high voltage section of Bally/Stern solenoid driver boards. Sometimes these go bad or just fall apart. GPE carries the trimmers for the Bally boards but the Stern boards are a little different. See diagram below.
I’ve looked at Digi-key and Mouser but I get overwhelmed and confused with all they offer.
Where do you get your trimmer pots? Which ones do you use?