I'm working on restoring a Gottlieb Central Park. While working on it, this symptom started up:

The 'ones' unit will cycle through to '0' then the coil in the ones unit locks on solid until I pull the power (to keep it from melting down, then it advances to '1' as the power goes off). I've had the ones unit apart 3-4 times already looking for a short or mis-adjusted switch, and just cannot find anything. If I plug the power back up, lights are off until I hit the replay button again, then the process of cycling through to '0' and locking the coil on happens again.

I have the schematic, but admit I have a tough time tracing what is (or should be) going on during the reset sequence.

Any tips of where I should be looking?

Thanks for the fast response! Will check. So just so I understand, are you saying that if a 1-point switch is stuck during reset, it can cause this symptom? Just intrigued and wanting to figure out why.

BTW, I should have admitted that it was working earlier, but a few other things were not working quite right and while tweaking switches here and there, this problem surfaced. So... makes sense this could be a stuck switch outside of the ones unit.

Found it! It was a switch stuck closed on a pop bumper relay (see pencil pointing at switch). Weird thing is the armature acts like it doesn’t want to move. I’ll take it apart to see what’s going on, but if I force it open to open the switch, the locked on ‘ones’ coil problem stops. Thanks guys for the quick, super helpful advice.

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Upon inspection of the relay assembly, I found that the plastic actuator for the switch stack had a fair amount of wear in the slot that pushes the middle switch. It seemed to be snagging on the switch blade, and obstructing movement. I tried filing/sanding the slot but ultimately decided to move the switch stack to one of the two unused positions engaging the plastic actuator (see relay on right in pic). It seems to be working fine. Now off to check and troubleshoot other switches.

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