The armature on this relay remains pulled-in after the relay coil is de-activated. If I release the armature, it does not stick again until the coil is re-activated. It does not stick when activating the armature manually. I have ruled out any sort of mechanical issues (dirt, corrosion, wear, etc). A stronger return spring did not solve the problem.

Has anyone seen this before and if so, what was the fix? I’m familiar with some of the homebrew demagnetization procedures, but I’m hoping there may be other options or something I’m overlooking. I would rather not disassemble this relay assembly since the parts on this machine are made of unobtainum.

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There is not any mechanical resistance when the armature is activated manually. The armature clearly remains attracted to the coil pole after the relay is deactivated. One they are separated, it will not stick again until after the relay is activated.

Thanks I will look at the switch adjustment closer.

There is an insulating pressboard sheet between the coil and the frame. This is a very original game and the relays do not appear to have ever been taken apart. I’m experiencing the exact same problem on two different identical relays.

I assume that the brass washer is to create an air gap so the flux is only attracted to the armature and not the frame. In any case the frame does not appear to be magnetized during relay operation.

I tried the degaussing method with a weller soldering gun without success. The armature plates are a bit oxidized as some have pointed out but the hinge interface is clean and the armature moves without any problem when operated manually, or after it is separated from the pole following a relay operation. I guess my next course of action at this point is a stronger return spring.

This is maddening.

No, the coils are 30V. No rectifier.

I made a double strong pot of coffee and decided to disassemble the relay.

Heres some pictures of the armature and coil. I am assuming the shaded pole and brass rivet on the armature are to limit coil buzzing. In any case, I cleaned up everything very well, banged on the armature with a hammer and waved it over the electromagnetic field from the old weller junior solder gun.

Upon reassembly, the relay functions and returns as it should. Troubleshooting is changing one thing at a time, but in this case I wanted to minimize taking things apart multiple times. So I’m not sure which one of the things I did solved the problem.

Questions, comments, speculations or insults welcome.

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Well the caffeine from my double strong pot of (https://redroostercoffee.com/) coffee wore off and so eventually did my repair! After 3 games, the armature started to stick again. This time I was sure that there was no dirt or crud holding things up (sorry, cash-riprock). So it was back to the drawing board.

What I figured out was that there was too much clearance in the armature slot where it slides onto the frame. This additional clearance (.021”) allowed the armature to move around such that the little brass rivet on the armature was no longer aligning perfectly with the coil pole when it was pulled close. I figured out that this alignment was key in allowing the armature to release since the brass is non-magnetic.

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I decided the best fix would be to make a shim to take up this clearance and keep the armature in position. I made a pattern and cut it out of .016” aluminum stock figuring that the additional .005” would allow for the correct action so it didn’t bind. I allowed a little extra on the sides to fold over the frame to keep everything in place.

The result was great! The relay now *snaps* open and close like it was designed. This is important since this relay controls the 1k/10k change over scoring feature between the two pairs of playfield bumpers. It’s fun to see the playfield light inserts dance back and forth during the reset sequence again.

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