I have a 1976 Williams Space Mission machine that i have working most of the way. I have two problems left i have not figured out. The first is the machine will only give free games at the pre determined scores on player 4 only. Player 1,2 and 3 it will not give free games when you get those scores. The second thing is the 100,000 light does not come on when it should sometimes. What actually tells the 100,000 light to turn on for each player. Thanks for any help.

Thanks HowardR for the reply. I got the 100,000 lights all coming on when they should now. It was dirty switches on the 100,000 relays. Now I need to figure out the 4th player only getting free games from the scores.

I looked at all of the 1000 and 10000 score reels for players 1,2 and 3. The boards don't look bad. They look just like the 1000 and 10000 boards on player 4. There is no gunk. It just seems weird all 3 players would have the same issue. It could be though. Is there anyway all 3 could be from the same single issue? If I don't get any suggestions to try I guess I will try cleaning the 1st player 1000 and 10000 reel boards in the morning. See if it makes the 1st player work. If it does I will do the other 2 players.

I was not able to get back to this yet. I am going to try to mess with it this weekend if I can. I will report back once I do. Thanks everyone.

Am I assuming correctly that the problem for 1-3 players has to be between the blue lines since 4th player works and it has to use all of the other stuff in the circuit? Thanks

20191207_094648 (resized).png

I am going to try to use the jumper wires to try to figure this out. I am a little confused on how the score drum units work. As far as knowing what score it is looking for to give a free game. Like how it would look if you had the first high score set to 114,000 and trying to trouble shoot it. What wires it would use on the drum units. Do they start from left on schematic and go 1 2 3 4 or maybe 0 1 2 3 ect. Thanks

I decided to try and clean the score reel units first and see. So I cleaned the 10,000 score reel on player 1 and then tried it and it worked right. So I thought I will try the same on player 2 and 3. I did and guess what they worked. So all 4 players will now award the free games for all three scores. Thanks for everyone's help