Quoted from Mervyn:I’m working on a sttng just now and the underfield diverter coil is burnt and so the game cannot load a ball into this position before game starts.
This is a very common failure mode on STTNG and is normally due to broken tieback wire to the 8 Driver board.
https://pinwiki.com/wiki/index.php?title=Star_Trek:_The_Next_Generation#Diode_.22Tie_Back.22_missing_causes_8-Driver_Board_transistor_to_fail