Symptoms: Would not trip at end of record. When selecting B7, it would also play D7 and vice versa.
Checked the switch continuity with an ohm-meter and the switch was not reliable. Since the prospect of getting a duplicate switch was slim, I opted to open it up and clean the contacts. It solved that problem.
Observing the selector pins under the mechanism while the owner pressed the selector buttons on the front of the jukebox, I could see that two solenoids were activating at the same time. With an ohm-meter, I verified that the B and D solenoids were shorted together. I unplugged the front selector switches and the short was still present. I removed the selector mech and realized the box attached to the bottom of the selector mech was the stepper unit for remote boxes. I unplugged the stepper unit from the selector mech and the short between the solenoids went away. The problem was one of the stepper relays was gummed up with old grease and wasn’t resetting to zero. It was stuck between B and D, shorting them out. After consulting with the owner, I manually moved the stepper to the reset position, not repairing it and leaving it gummed up. The owner was never going to use the stepper unit, and I couldn’t simply leave the stepper unplugged because, according to the service manual, there needed to be a jumper plug installed.
I replaced the needle, which improved the sound substantially.
Location: Boulder, Colorado