Recently acquired a Williams Stellar Wars. Playing well. I thought I'd like to change from 3 ball to 5 ball game and set the game to free play. However I found that the Diagnostic Switches inside the coin door are not working.

Auto Up / Manual Down toggle switch, Advance button and High Score Reset buttons inside the coin door. They don't seem to respond to any input.

Any ideas why the Diagnostic switches are not functioning ?

Yes I did get this game at Expo. I'm not much of a Solid State mechanic other than fooling a little with some Gottlieb System 1.

Sorry for the delayed response. I have played the game 3 ball for quite a bit. Today being rather cold and having the day free I moved Stellar Wars out of my row of games for a look see.

After a little on line search I found where IC5 and IC18 are located on the MPU board. IC5 appears to be a soldered in connection and appears solid and fine. IC18 is sockected and seems to be very tight. I couldn't budge it from it's socket and didn't want to pry it. I did see that there was some cleaning done on the board at some time under the edge of IC18 socket on the right side. I would guess that a replacement socket was maybe installed at some point. All appears well to the eye.