check 12v test point on your power driver board again.
If you have power present
Are you sure all connectors are back in correct locations? not one pin off (ask why I ask
)
Otherwise I would say you have a flaky optio transmitter on the trough board. Demo man has how many trough optio's is it 6 if I remember correctly, one for each ball plus another for the exit.
Are you seeing all 6 optio's in your switch test?
If there is a flaky optio its more likely the transmitter than a receiver in my experience. They are available to be replaced and can be fixed for pennies on the dollar vs replacing the whole board.
Just because I have run into a bunch of this lately
Any corrosion to resistor / diodes / chips/ chip legs on the cpu under the battery?