(Topic ID: 220839)

Skylab- Score motor and relay Help Needed

By Pintor

4 years ago

Topic Heartbeat

Topic Stats

  • 15 posts
  • 6 Pinsiders participating
  • Latest reply 4 years ago by Pintor
  • Topic is favorited by 1 Pinsider


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#1 4 years ago

Hello Pinsiders,

I’ve been working on my first EM pinball Skylab and can’t get it to play correctly. Here’s where I’m at.

Turn the machine on
Press the left flipper and the light comes on
Lock relay engages

Sometimes pressing the start button does nothing and I have to manually latch the game over relay to get things moving.

Other times I get lucky and pressing the start button engages the coin relay, which in turn engages the reset relay, game relay, game over relay, and score motor. A credit will decrease and the score reels reset.

However, even when that happens, the outhole will not kick the ball to the shooter lane and the score motor will run endlessly until I manually pick up the ball and put it in the play field.

After the ball drains into the outhole, the score motor again runs endlessly and the “balls to play” does not count down and remains at 5 balls unless I manually engage the ball index relay and the outhole relay.

I’ve had a friend with 30+ years experience with jukeboxes and 7+ years experience with pins look at it and together we haven’t been able to figure it out.

All contacts have been burnished, relay leafs adjusted, all steppers and score reels were disassembled and cleaned, fuses checked. We installed a new chime box which sounds beautiful and works perfectly when the ball is in play (after I manually lift it out of the outhole and place it in the play field). I’ve tested the outhole by engaging the outhole relay manually and the solenoid works.

I am completely stumped. I’ve spent hours looking at this and can’t figure it out. I’m going to upload several pics starting with the score motor. I can’t help but think it has something to do with the contacts on that.

This is my first EM, it’s a true piece of art, I really want to get it running again.

Thank you in advance!

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#2 4 years ago

More pics

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#3 4 years ago

And finally. I hate to just spam a bunch of pics on here. I’m hoping the answer has been staring at me the entire time.

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#4 4 years ago
Quoted from Pintor:

All contacts have been burnished, relay leafs adjusted, all steppers and score reels were disassembled and cleaned, fuses checked.

You may have created some new problems doing that, but the kickout problem is likely caused by score motor sw. 4A. so check that for cleanliness and good contact.

And check these circuits for your ball count problem.

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#5 4 years ago
Quoted from Pintor:

Sometimes pressing the start button does nothing and I have to manually latch the game over relay to get things moving.

Sounds like there's an unreliable connection somewhere in the Coin relay circuit:
Skylab Coin relay (resized).jpg
I'd check those five switches carefully along with any jones plugs, solder tabs, etc.


#6 4 years ago
Quoted from Pintor:

All contacts have been burnished, relay leafs adjusted, all steppers and score reels were disassembled and cleaned

Sorry but that was a mistake. This forum is full of posts from people who tried shotgun cleaning & adjustments, and caused more problems than they were originally trying to solve.
What to do instead: Slowly and carefully diagnose one problem at a time and then fix only that.

MarkG is right. Check that circuit with Alligator clip jumper wires.

#7 4 years ago

As the score motor is spinning, does the outhole relay pulse on each revolution or does it engage and latch?

#8 4 years ago

currieddog MarkG HowardR
Thank you, I worked on tracing back the problem like you guys recommended last night.

Quoted from dhutton:

As the score motor is spinning, does the outhole relay pulse on each revolution or does it engage and latch?

Thanks dhutton no the outhole relay doesn’t pulse or engage with each revolution of the score motor. I’ve always had to manually engage the outhole until...

I noticed last night that the bonus relay was pulsing with each revolution when the outhole switch was triggered.

I went ahead and manually pushed the white plastic plate of the bonus relay over further while it was pulsing and to my surprise the outhole relay engaged and the outhole solenoid fired!! Everything appeared to work as it should. However it would only work when I manually pressed the bonus relay.

I took pictures of the bonus relay. I don’t see any obvious issues with the coil, leafs or contacts, but I have to think there’s something wrong with one of those components if the bonus relay is pulsing with the score motor but doesn’t engage the outhole relay unless I move the white plastic piece of the bonus relay over further while it’s pulsing.

Before I do anything further I wanted to check back with all of you.

Thank you!

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#9 4 years ago

Hi - my first post to Pinside. I'm the person helping Pintor with this machine. I have been a pro audio electronic technician for 30 years, and I have been also servicing Jukeboxes since the 1980s. But Pins are a recent thing for me, and there is so much to learn. The EM machines are especially frustrating to learn on, because of the complexity.

What has been done to the machine so far was indeed necessary. It has sat idle for decades. All of the score reels, features stepper, credit stepper, coin motor ware locked up solid with dried out grease. The EOS blades on 2 of the score reels were broken off and gone. Every contact was black as coal with tarnish. Someone had buggered up the stack switches on a number of relays in the backbox.

After putting everything back together, I successfully played the machine - racking up about 160K points. Everything was working great, that is, until the last ball dropped and game was over. At that point, the machine went into tilt. Would not reset. When I got it to reset, the ball release solenoid no longer fired, and the score motor ran continuously. I confirmed the circuit to the ball release solenoid was good back to the cam switch on the score motor. From there I traced it back to another set of relay contacts ( can't recall which ones now ) I told Pintor that if I had been working on pins as long as I have been doing jukeboxes, that I would know exactly the problem. I wish that was the case. I was tired at that point, so we wrapped it up for the day. He is getting close. I'm confident that there is either an intermittent solder, cracked wire, bad coil causing the problem. I'm sure that is obvious to those of you that are seasoned with these. I have to pour over the schematic soon and trace out the rest of the circuit. But so far, the problem eludes me.

Any insight toward a solution is greatly appreciated. I have a lot to learn.

#10 4 years ago

I would check the make/break on score motor Index-E, and perhaps the rest of these circuits.

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#12 4 years ago

Hi Jukester

Welcome to pinside!

Can you have Pintor stop posting endless pictures? They don't add anything to our understanding of what's going on and just make it slower to find relevant posts.

Meanwhile, if the Ball Release coil doesn't activate when the Outhole relay is activated, inspect and diagnose this circuit with Alligator clip jumper wires.

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#13 4 years ago

Duly noted, sorry for all the pics, I will leave the pic posting to the experts

#14 4 years ago

Thanks Howard. The problem I believe is somewhere after the outhole relay. I traced the the blue white circuit back to the C 4 score motor stack, then the grey green circuit back to the outhole relay. I didn't have time to dig farther. but up to there it's solid. The red side of the Ball release solenoid shares the circuit with the flipper solenoids - and those work fine. So I have to just keep digging until I find something. Thanks

1 week later
#15 4 years ago


Just needed to adjust the EOS stroke on the advance unit stepper and one of the contacts on the bonus relay. After that everything worked except the game over and match lights. It took a while but I figured out the “ball to play” stepper was missing a washer. Once I replaced that everything started working.

Thank you everyone for your time and help!

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