The top two AN displays work fine but the bottom two got nothing. I've reflowed all the headers and tested that the ribbon cable and MPU are good by using a rottendog replacement display (all four work fine on that one).
Is there a single part they have in common that might cause both to be dead? Looking at the 4050 or 7180 chips, perhaps? Nothing physically damaged on the board (no toasted resistors, etc.)
Be gentle - primarily a vid guy here!