Had/have similar issue — when balls were popped up to battlefield, kicker Fred every time I moved the paddle. Tried everything from connecting cables, to opto solder, motor driver board, rebuilt power section with new caps.. annoying as hell. I finally got it fixed for a long while by replacing one of the Optos (after already previously trying that). Comes back occasionally now though.. maybe solder flakiness now. your issue has to lie somewhere in those connections / components — keep at it, youlll find it. Is your 12v ok?