>I know I've seen pictures of this board with the little auxiliary board somewhere before.
I am certain this was posted on emuchat forum a few years ago when TNT Amusements had a cocktail table Tournament Table listed on ebay as a buy-it-now option. It was already sold before anyone could find out the exact name of the company that marketed the game.
One of the photos on the ebay buy-it-now listing of Tournament Table showed a closeup of pcb (seated inside the cocktail table) with all its adjustable pots and it matches the same model that you won there.
The smaller board's function likely operates in same manner as the game function select board that is used with URL's Video Action. The board gets the data from the external button and switch select options that a player chooses before game begins. The board then sends the data to the main logic board and the main logic board loads up the desired game and the difficulty settings, and the number of players etc. as play begins.
>On the board it says, "Magnetic Corporation of America," but nothing really comes up in Google.
I thought it may have been related to Magnavox, but I don't believe so. Magnetic Corporation of America was also involved with Williams Paddle Ball....see bottom right of page 1 of Williams Paddle Ball stapled instructions sheet.
I am not sure if that may have been a predecessor name for the videogames division department of Williams or if Magnetic Corporation of America was manufacturing pcbs for various game companies like URL was doing for Allied Leisure, Electra and Stern etc.