Bought a Stern Kiss (Pro) in 2017 - 3rd owner and it's been great. Added a Mezal Mod to Gene's tongue that lights whenever the ball triggers the spinning disk under Gene's head. Worked perfectly for 4 months, but in the last 3 months I started hearing a buzzing sound each time the ball would enter the head area and the light would flash almost constantly. But for the past 2 months, the buzzing noise has stopped and there is no light triggering. When testing the opto's by pushing the ball up to the spinning disk area - Nothing happens. I am definately not getting any spinning on the ball and it is going to the VUK each and every time the ball is passed up that far. Does this mean I will need to get a service done on the opto's? Should I remove the Mezal Mod and test again? Everything else is functioning perfectly on the machine. Appreciate your feedback.

Could anyone enlighten me as to exactly what an opto looks like? This is my first pin and the manual I got with my Kiss Pro is just a parts and service manual produced by Stern.

Thank you very much TomGWI and Kiss73