It is a case of following the instruction in your manual for the adjustments on the Stop Plate Assembly.
I would remove your search unit and then the stop plate assembly and inspect the wipers behind it, clean the slip rings on the back of the assemby with a pencil rubber (eraser) and then check the wires soldered onto the slip ring for any dry joints (cold joints USA), inspect the two micro switches for operation, mechanically and electrically.
Check and clean the two solenoids.
If all checks out refit and test the operation of the jukebox. Are you sure that the search unit is pushing out the correct pins?
Regards
Alan
Alan Hood
ami-man
UK