The score motor is the very last thing you should ever do adjustments on when troubleshooting. Especially if you don’t know what you are doing, (first game), you will open up a can of worms that you will never resolve.

So for EM games, a switch that is normally open will close when the motor runs. It will become energized when the cam rotates the trough or notch around. Some switches are normally closed and open in the same way, thus breaking the circuit and causing the motor/scoring to stop.

It sounds like you might have a stuck switch somewhere else on the game. I would check all those first. Some games have a metal stiffening blade between the leaves of the switch that could be causing a short. Check for that too. Also, please let us know the game and post pics of the motor and schematics to help better diagnose the problem. Info on how many points are being scored is also very helpful. I wouldn’t worry too much about the motor as long as there aren’t any coils locked on.

Figure this problem out first. It rarely has anything to do with a switch on the actual motor itself.

Read this for starters.

http://www.pinrepair.com/em/index3.htm#motor

A very first, quick, and simple test you could do is manually set all the score reels to zero with the game off, then try to start the game. Chances are there will be no change in behavior, but all you’ve lost will be a few minutes.

I’m assuming the score reels don’t reset currently.

If this is for Playmatic Rio, one or more of these switches or relays is stuck closed. Which one(s)?

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I don’t want to hijack this thread, but I just want to take a second to thank you for how quickly and often you’re willing to help out in these EM repair help forums, often with detailed schematic excerpts. I imagine it’s quite a bit of work to go through the trouble, but it’s always appreciated.

If index c was always closed, the score motor will continue to stay running. It’s the motor runout switch looking for it’s home position and open.. along with all the other switches listed above.

pinballdaveh is right. The reason I typically don't include it is that when the motor is running it's closed most of the time, which could cause beginners to think it's the problem when it isn't.

Each relay that HowardR has red circled above will have a normally open switch with a Blk-Slate wire(s) connected to it. When the switch is closed even if the relay isn’t pulled in,the score motor will run. Clean and adjust switches if needed.

Just listen to Howard and do exactly what he says, and you will fix the problem.

Make sure your on the correct cam. The index cam is the 2nd cam from the motor. On this machine the first cam is the impulse cam ( unlike Williams where the impulse cam is on the far right ). Find the black-slate wire to verify the correct switch. Adjust switch to open on the low dwell of the cam home position.

Think of it this way: the schematic is trying to show the state of all switches throughout the game at one point in time. It should be a state that the operator can reproduce. In the case of the motor, it shows how the switches are when the motor is at the home position. Some switch stacks will be lifted up and some won't. That's not the same as "normal" in terms like "normally open" that apply to how the switch blades are configured when not being actuated by an outside pressure.
.................David Marston