A few months ago I took a road trip to buy a rare 1947 Exhibit Coed machine - a flipperless game released just 14 days before Humpty Dumpty that has some really cool features (shoutout to @amkoepfer). Once it was home, I set about cleaning it and getting it back into working condition but one problem eluded me - the 1K unit wouldn't re-set when a new game was started. The 10K unit (which has a reset coil) would zip back to zero, but the 1K unit would show whatever value was left from the previous game.

I posted a question on an EM tech thread and Pinsider bingopodcast agreed to be the Obi Wan to my Luke in this little quest. He turned out to be more like the Virgil to my Dante. We pored over the schematics for weeks, poked and prodded and tested dozens of things and I even made a giant color-coded inventory in Excel of all the connections to all the relay points in the game.

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None of it helped. Odd as it sounds, it seems that this game just wasn't designed to have the 1K unit reset. Once we reached this point, I asked a question: What do I need to do to make the unit reset back to zero? @bingopodcast's answer: you'd need to wire a new relay into the machine. Okay, I said. Let's do it. So I hopped on Ebay and picked out a group of Williams relays. Three days later they were at my door.

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I decided that the big one would be easiest to work with. The first step would be to wire the relay coil so it activates when a a new game is started (early games like this call it "shuffle.") The shuffle switch is directly connected to the 10K reset coil, so I wired the new relay's coil to that.

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Now the new relay closes when shuffle is activated. The next step is to get the new relay to turn the scoring motor. Simple enough - just wire one of the relay switches to the switch that starts the score motor.

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Now when shuffle is activated, the new relay closes causing the score motor to turn. Next, I needed the score motor to activate the 1K advance coil. There's a 5K relay that already has this function, so I connected a second relay switch to those leads.

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Now when Shuffle is activated, the new relay closes causing the score motor to turn and causing the 1K unit to advance. The problem is that it only advances for as long as I hold in the shuffle switch and it doesn't stop at the zero position. I need to set up a "hold" switch that will keep the new relay closed until it reaches zero position and then release it. Unfortunately, there's no lead on the unit that does that.

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The row of lugs at the bottom lead to the backbox lights for 1K through 9K. The last one leads to an EOS switch, causing the 10K unit to advance when the 1K unit reaches zero. I was stumped until I had a look at how other wiper units handled this kind of situation.

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This is a unit on the underside of the playfield that controls a variable scoring feature. You'll notice that instead of individual buttons, it has a continuous strip for a lead. This sparked an idea and I headed out to go shopping.

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Before pinball I had been into stained glass, which uses adhesive copper tape. I was all out and none of the stores nearby sell it. My second choice was a special magic marker I had seen once with conductive ink - draw a circuit on paper (or plastic or fabric or whatever), attach a battery and it will power a light or a small motor. My local hobby shop didn't have that, but they did have this thin sheet of copper foil. I traced the shape of the arc on a piece of paper, cut it out and used that as a template for my new lead.

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It turns out that making two little arcs would be easier to deal with than one big one. I glued them to the bakalite with rubber cement. The gap in between is a zero position.

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Next, I wired the arcs together and to the new relay.

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And it works! Now when I activate shuffle, the new relay closes, the motor spins, the 1K unit advances and it doesn't stop until it reaches its zero position! Hooray!

Here's a video of the game in action!

I thought you were kidding around about programming a music soundtrack into an EM, but now I'm not entirely sure.

The music in the video isn't coming from the game - I added it in the video editing process. The songs are "Dizzy Fingers" and "Sing Sing Sing", both by Benny Goodman.

I'm not worried for now - there's a lot of leftover copper and I can always use gum wrappers if that runs out.

I chose rubber cement figuring it would be easier to clean off and re-apply if I ever need to.

What? No question! RDA all the way.

Here's another video taken from a higher angle, so you can see more of the playfield in action.