I worked on the machine a little last night. I think I have determined that it is a two part issue. The left battery in the 3 battery pack terminal has a loose connection so if I clamp that left battery top and bottom the settings get saved. So the pin so far in the corner it would be difficult to solder in place and that massive board has 100 wired connections so if I attempted to remove the board to solder in the workshop on a bench with more light, then I'd likely break something else on the board or wired. So rubber bands to the rescue it was.
The 2nd issue is the advance button and/or the auto-up/manual-down button. The advance button only moves in one decrementing order. If you engage the manual-down button, the advance button is supposed to increment and it does not. Furthermore, after setting free-play on my other 2 Williams pins it allows you to exit to the Game Over mode and begin playing pinball regardless if batteries are holding charge or not. On the Banzai Run, you can never exit the adjustment mode so batteries ARE required and you cannot play pinball for free until you power off under the game via the switch. So that is the 2nd issue basically why does the advance button only decrement and not increment, and why can I never leave adjustment mode without physically powering off the game?
Thanks.