I just realize that there are different filter boards for Model 2B CRX. 839-0773 and 839-0946 are the current part numbers that I found. 839-0773 has 3 connectors to the game board, while 839-0946 has 2. I tried 839-0946 on Last Bronx board and some controls are missing. Did anyone have any inputs regarding the different filter board for different games?