Hey guys, working on a Gottlieb Duotron, had all kinds of issues when i first got it, score motor was running constantly due to a stuck switch, some other features werent working properly and were fixed when I adjusted some relay switches. However now I am at an impass, the game does not score 500 points consistently, sometimes 500, sometimes only 300 or 400. Also, the bonus does not always accumulate or score properly, meaning if a switch is supposed to add bonus, sometimes it will sometimes it wont, and then the bonus that does accumulate does not score properly, for example if the game shows 10k bonus it may only score 8k at the end of the ball.

My gut feeling is that something is out of alignment with the score motor, maybe the 1A switch? I have cleaned all the switch stacks on the score motor and from what i can tell they all open and close properly when the motor turns. However I am still a relative novice when it comes to working on EM machines and would appreciate any help or advice. If any pictures or video would help I can provide that. Thanks a lot.

I double checked the "500 point and add bonus unit relay" and it appears to be opening and closing fine.

I did notice something, the game will score 500pts correctly every third time, i hit a few 500 point switches and found that I would get a random number two times then it would score 500, for example 5-n-n-5-n-n-5-n-n-5 etc. This again points me to the score motor (i think) and something with the switch stacks but Im not sure what.

Still stuck on this..