keeping an eye on this thread. I've rebuilt my lower flippers on black knight, new coils and all, and they have always been weak. I think I remember something about a possible miss wiring of the lower flipper coils from the factory back in the day that would cause them to be weaker? Just as your machine is, it will barely get the ball up the ramps to the upper play field.

Had this issue with my Truck Stop as well, but then read that the balls should not be the typical standard size ball and replaced them with the proper size balls as per the manual, and I could hit everything. Truck Stop was the same where I had rebuild the flippers completely and the ramps were still hard to hit.

I did try those smaller balls in the Black Knight, even though they aren't supposed to be in there, and it always had trouble reading that they were there when the ball drained or at the top where you lock the balls for multi ball. So, don't bother trying the smaller balls to adjust for the weak flippers!

I'm going to have to have a look at my flipper switches. I may have overlooked those when I rebuilt the flipper mechanics originally.