(Topic ID: 250129)

I MacGyvered a new relay into an EM Machine

By TopMoose

3 years ago


Topic Heartbeat

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  • 21 posts
  • 8 Pinsiders participating
  • Latest reply 3 years ago by TopMoose
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#1 3 years ago

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!

#2 3 years ago

Great post, i love this kind of stuff! Thanks for sharing!

#3 3 years ago

Here's a video of the game in action!

#4 3 years ago

Nice, good work! Those bumpers at the lower left and right are funky!

#5 3 years ago

Very impressive!

#6 3 years ago

Awesome work!

#7 3 years ago
Quoted from TopMoose:

Here's a video of the game in action!

Love the music that starts- Are you using a sound module with an SD card?

#8 3 years ago

Great work reviving that old gal!

#9 3 years ago
Quoted from gdonovan:

Love the music that starts- Are you using a sound module with an SD card?

#10 3 years ago

Thought of doing it myself with a few pins.

Device similar to this-

ebay.com link: 1PCS WTV020SD Audio Module micro SD Card Sound Module Game Device Module

You upload your audio file, wire to a trigger and enjoy. I have a proton pack prop that uses a device like this.

#11 3 years ago

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.

#12 3 years ago
Quoted from TopMoose:

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.

Oh no I was dead serious.

You timed it just right at the start of the video. I have a Williams Touchdown that I was thinking about programming a module to play an NFL broadcast TV clip "TOUCHDOWN!!!!!!!!!!!!" when you made a touchdown in the game of course. Would be very easy to trigger from the field position unit. Would be very easy to get a unit with several trigger inputs and have background music playing too.

I tinker around with movie props time to time, have a walkie talkie that plays several movie clips from Ghostbusters. The module has an SD card with several wav files and it cycles through them when you key the mic.

I think your game would be pretty awesome if it started playing that music when it was credited up, was a great choice.

#13 3 years ago

The only thing I'm wondering is yours a 50 volt game? Not sure but those relays you picked up might be of the 24 volt variety. Which will work, but perhaps not for long. I've seen too many 24 volt coils in 50s volt games already.

If you've got it all figured out, carry on...

#14 3 years ago
Quoted from o-din:

The only thing I'm wondering is yours a 50 volt game? Not sure but those relays you picked up might be of the 24 volt variety. Which will work, but perhaps not for long. I've seen too many 24 volt coils in 50s volt games already.

It's a 30V game.

Always happy to help TopMoose! Glad you got it working!

#15 3 years ago
Quoted from bingopodcast:

It's a 30V game.

Interesting!

#16 3 years ago
Quoted from o-din:

Interesting!

United, Exhibit and Genco tended to use 30V.

United and Genco have some 17V coils (mostly in machines with 17V lamps).

In this case, the 24V relay will work just fine. I'd be more concerned about the copper strips falling (eventually). Those metal strips on the steppers are a long strip of metal with legs, and the legs are wrapped around the stepper itself on the back side. To make a more permanent mount like that, you would drill the stepper and fold the legs around. I don't have a lot of experience with rubber cement and I've been told it's a lot stronger than I believe.

#17 3 years ago

Thanks also for sharing the gameplay video! It sure is a lively machine. Looks like a lot of fun to play. Some great ball movement/opportunities at the bottom of the playfield.

Exhibit had some really neat flipperless designs.

#18 3 years ago
Quoted from bingopodcast:

United, Exhibit and Genco tended to use 30V.
United and Genco have some 17V coils (mostly in machines with 17V lamps).
In this case, the 24V relay will work just fine. I'd be more concerned about the copper strips falling (eventually). Those metal strips on the steppers are a long strip of metal with legs, and the legs are wrapped around the stepper itself on the back side. To make a more permanent mount like that, you would drill the stepper and fold the legs around. I don't have a lot of experience with rubber cement and I've been told it's a lot stronger than I believe.

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.

#19 3 years ago

So the only real question that remains, is this the new MacGyvered or the old MacGyvered?

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#20 3 years ago
Quoted from o-din:

So the only real question that remains, is this the new MacGyvered or the old MacGyvered?[quoted image]

What? No question! RDA all the way.

#21 3 years ago

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

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