I've got a Tri Zone acting very strange. Sometimes I can turn it on and get it to play a few full games where everything works perfect. However, most often when I turn it on the GI will come on and the Master and Player 1 displays will come on. Player 2-4 displays stay off. Also, the sound always works when I do the sound test even if the game is acting odd. When the game does boot properly sometimes it will keep resetting itself.

So I rebuilt the reset section of the board, reflowed the solder on the 40 pin connector, and replaced the batteries. Game now works great!