The power for the Diverter coils is from the Aux Driver board - the little board mounted in the top right hand corner of the head. Check the transistors there.

Also - if the wire looms for the cannons have breaks in them, then you will get these issues.

So check ;

Single drop target is working ?
Divertors are not stuck on - you will hear / smell this - check Aux Driver board.
Cannon looms - bothe left and right - check them for continuity. I ALWAYS replace these looms and most of the problems disappear.