My North Star worked perfectly until it recently developed a new problem. On start up, the score motor runs without stopping.

Background: I am a noobie. I admit I am a novice at this, but I used to fix IBM Selectric typewriters 35 years ago, so I have some modest skills. I bought this machine several years ago, and it was dead and very dirty, and I carefully cleaned everything, dressed and adjusted every set of contact points in the machine, stripped, cleaned, waxed and polished the playfield, replaced broken plastics, rebuilt pop bumpers and flippers, and the machine worked perfectly and was (is) a great playing machine.

I have had to diagnose and repair several small problems since the refurb, so I am not totally unfamiliar with the machine's operation, but this issue has me stumped, and I am looking for guidance from folks with more experience, and better troubleshooting skills than I have today.

The score motor contacts at 1C are all correctly adjusted. The score reel mechanisms all have the correct contacts opening and closing at nine and zero score positions, and reset to zero upon start-up.

The game credit reel mechanism also is correctly adjusted, with the exception of the 'short' pair of contacts, which were adjusted to stay closed for free play.

The coin drop and ball return count contacts, and all of the relay contacts appear to be opening as closing correctly.

The fuses have all been confirmed good with an ohmmeter. The tilt switches are correctly adjusted. I suspect that am missing whatever it is that is not resetting and opening the circuit to the score motor, but this is just my suspicion, and I cannot find the problem from 'reading' the schematics.

The start button will not initiate the start sequence, but if I manually nudge the Hold relay or the Extra Chute relay, the ball release coil is energized, the score reels reset to zero, and then the score motor cycles continuously. Sometimes the relay switches are reset by the large solenoids, and sometimes not, but they have all been manually reset, and all switch contacts appear to open and close correctly when manually switched open and closed.

I've always been able to correctly diagnose problems in the past, possibly through persistence and sheer luck. It could be a bad coil that is not energizing on the startup sequence, and I am not smart enough to know what to look for, or how to interpret this from 'reading' the schematics, and I don't have the knowledge of what is supposed to happen during the game start-up sequence.

Does anyone have any advice for a noobie on what to look for without having to pay a technician $100+ for a house call?

Many thanks.

North Star player and EM pinball fan,
ShoreThing