Hi there , seems like it's not reading the ball2 , chech line up of IR diode and opto coupler , easiest to do taking the unit out
Reason is that when I got the new board it does not line up to well with holes in the chassis so had to tweak it a bit.
Have been troubleshooting the same , I had failure on the IR board but also the coloum it self , but yours detect all the other so coloum should be fine , believe row if fine also on your game as it look same as mine in test mode , now that all work.

Regards
Terje