Quoted from JB-7X:Check the GI driver board on the center of the play field. When mine went out it was the 3 pin connector on the upper right corner. Stern sent me a new harness and board. While waiting for the delivery I bush fixed it by sticking a small optical screwdriver in the end of the connector to bend the contacts more so they better secured to the posts when clipped on.
I have also read people saying the data cable from the GI board to the back box has gone bad on them also causing this same issue but tha wasn’t my scenario.
I’d just try to wiggle the 3pin connector while the game is turned on, if you get a flicker that’s probably it.
This just happened to my Met. Funny thing is a couple months ago I noticed one of the gi bulbs was out then today all of them. Reseated the cables and now all gi is working again.
Phoenix, AZ
