I’ve been troubleshooting my Sing Along and think one issue relates to the ones score reel. When the machine is running and I trigger one point scores the machine has trouble getting back to zero and tends to blow a fuse. When I work the reel manually it moves freely and clicks to the next number, until back at zero. At that point it will not click and move forward right away but does after 4-5 tries. This had been working fine until recently. Could this be an issue with the nylon gear and rack or something else? Opinions welcome!

Thanks. I have pored over Clay’s guide quite a bit the last few months. I gave the unit a good cleaning and it runs smoother now. The issue now seems to be the coils. Both the N relay coil and the score reel coil stay energized.

At reset. I unplug the machine fairly quickly to avoid burning out the coils. Hundreds will score but triggering ones does nothing.

No changes on the playfield prior to this problem arising. I've verified all switches are open. I haven't tried unplugging the playfield yet but will give it a shot.