I recently replaced my Williams 5 bank opto board with a with a Great Lakes Modular board.
Game worked perfect for a week or two.
After that once I hit any of the 5 upper playfield targets the game does not register that the target was hit.
The target will stay down for the remain amount of that ball. Once a new ball is started all 5 targets are completely reset.
I have reseated all connections and the issues remains.