On my Bally Twin Win pinball game the RESET relay will not de-energize during the start up sequence. The hold circuit does not open.
Otherwise, if I manually trip the RESET relay the game goes into PLAY mode and is OK.
The attached photo shows this circuit. I have traced the problem to the yellow wire at motor switch 8B (shared with motor switches 8A and 8C). With the machine hooked up to play (all Jones plugs installed) switch 8B never breaks the circuit from cam action, even though the switch does completely open. I can replicate this manually with the game off and opening the switch.
I pulled the bottom board out and unplugged all Jones plugs.
Now motor switch 8B works correctly. When open it does break the circuit. The switch is OK.
Plugging in the jones plugs one at a time I found the one causing the ground. It goes to the playfield. The offending pin was located and it is the ground pin that connects the playfield to the bottom board.
I traced that wire onto the playfield and it goes to the drum unit in the attached photo. Is this the Feature Drum Unit listed on the schematic? The offending switches were not open, and when open the motor switch 8B looks OK. So I adjusted the switches. Haven't tried it yet.
Thanks.
Alan