(Topic ID: 292571)

Gigi sequence question/problem

By EMsInKC

2 years ago


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  • 16 posts
  • 4 Pinsiders participating
  • Latest reply 2 years ago by MikeO
  • Topic is favorited by 1 Pinsider

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  • Gigi Gottlieb, 1963

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Gigi number relays (resized).jpg

#1 2 years ago

On the 1963 Gottlieb Gigi when you light up all bumpers of the same color, that gives you an advance and lights the special alternating on the side rollovers.

Mine has what I think is an issue, and from the schematic I cannot figure it.

Once all bumpers of the same color are lit, the other color bumpers score but will not light until the ball drains and the bumpers reset. This is the case for my game EXCEPT when you hit the number 2 yellow bumper when all the red bumpers are lit. That yellow bumper lights up and the special goes out, and the bumpers stay as they are once the ball drains. The converse is not true. If the yellow bumpers are all lit, hitting any of the red bumpers does not do anything other that scoring that particular bumper. All the yellow bumpers, and the special, stays lit until the ball drains.

There is a sequence relay that energizes when all bumpers of the same colors are lit. For some reason when the number 2 yellow bumper is hit, the interlock relay for the red/yellow number 2 bumper is changing state and allowing the yellow bumper to light, where that doesn't happen for any other bumper.

I cannot figure out from the schematic what it is in the sequence that is supposed to keep all the bumpers of one color lit and not allow the interlocks to change state. Anyone who can read schematics better than me, your help is appreciated. I thought at first that maybe vibration was causing the armature to slip, but I put a piece of paper in front of the yellow number 2 interlock coil and it would not change state, so the coil is energizing.

#2 2 years ago

I don’t have a schematic for Gigi and so could you post photos of the parts with the circuits of the interlock relays for the bumpers and the sequence relay? I am only guessing, but it seems that a switch associated with one of these relays is likely to blame as something should prevent that yellow #2 bumper from doing what it’s doing.

#3 2 years ago

Does the 2Y/#2 Yellow interlock relay use the same coil (A-6821) as all the other yellow interlock relays (1Y-7Y)?

If so, does it have the same resistance as the other yellow relay coils? Although it's often not true I think in this case you can reliably measure the coil resistance of the yellow interlock relay coils in circuit without disconnecting one solder lug.

/Mark

#4 2 years ago
Quoted from tfduda:

I don’t have a schematic for Gigi and so could you post photos of the parts with the circuits of the interlock relays for the bumpers and the sequence relay?

This is an unusual circuit:
Gigi number relays (resized).jpgGigi number relays (resized).jpg
There are seven numbered interlock relays to keep track of the 14 bumpers. Each interlock relay has a red and a yellow coil (e.g. 1R and 1Y for the #1 bumper). When a red bumper is hit the red coil in the interlock relay fires and when a yellow bumper is hit the yellow coil of the interlock relay fires. Normally when any of the 14 bumpers is hit and one of the numbered interlock relay coils fires, the P/Series relay also fires. Notice that the P relay is in series with the 14 interlock relay coils so two coils wired in series have to fire on the same 24 volts usually used to fire a single coil. No problem, although special series coils need to be used for this to work since normal relay coils require a full 24 volts.

Elsewhere in the schematic, once all seven numbered relays are on the same side (red or yellow) the G/Sequence relay fires. This flips the Make/Break switch in red above just before the P relay coil, effectively removing the P relay from the circuit. But instead of the P relay firing when a bumper is hit the Make/Break switch instead lets the N/1 Point relay fire. Normally the N/1 Point relay is fired whenever a bumper is hit and the P relay fires (through a switch on the P relay), but with the P relay out of the picture the numbered interlock relays have to fire the N relay themselves.

This is where things get tricky and I'm not sure how it's supposed to work. Normally the N/1 Point relay is fired alone with the full 24 volts through switches on the 1 point rebounds or whatever. But once the sequence is complete and the P relay is cut off, the N/1 Point relay needs to share its 24 volts with one of the numbered interlock relay coils. The N relay uses an R20-4 coil which is a standard relay coil so I'm surprised that it can work in series with another coil.

To make things more interesting, it looks like after the sequence is complete (G relay has fired) the bumpers still send current through the numbered interlock relay coils and on through to the N/1 Point relay. But based on the rules it seems that once the G/Sequence relay has fired the interlock relays should not change until the ball drains and the G/Sequence relay is cleared. If that's the case then the interlock relay coils have to work when connected to the P relay coil but not work when connected to the N relay coil even though current is passing through them. That would be a delicate balance. So if the #2 yellow relay coil is different than the other yellow relay coils that might explain why it fires even after the G relay has fired.

BTW, the I and II Sequence Reset relays shown are even more unusual in how they work, but that's another discussion entirely.

#5 2 years ago

Mark, I am pretty sure all the coils on the interlocks are the same. I have not however tested the resistance on that one coil. It should read out properly even in circuit as you said.

I had all the basics of this figured but I did not see that the P relay was in series. It's without a doubt a unique circuit. I think it was working ok then this problem cropped up.

Those interlocks were a dog to get right. They're held in the relay rack by the screw with also holds the red bumper coils in place. I was having an issue where the lights were not changing properly and I found that you have to get those coils in there just right or the latch/trip action just won't happen. It was fiddly to say the least.

Mike O told me this was one of the most complicated logic games and he wasn't kidding. I was surprised it worked as well as it did after the restoration given that the playfield was restored so I had stripped all the mechs off the underside. It looks simple but it isn't. Kind of goes with the game play. Looks easy but it isn't. And it is a totally different kind of game play from what came later with all those dead bumpers. This game really shows the genius of Wayne Neyens.

I'll check all this out and report back.

#6 2 years ago

The I and II are indeed different in how they work. Fortunately that one I understood and got that to work to reset the sequence just fine. It only resets on a drain when the sequence is completed. Otherwise he bumpers remain as they are.

I couldn't understand at first why a manual ball lift game had an outhole switch since most manual lift games use switches in the trough to track balls played. We associate outhole switches with ball return kickers in later games. Then I looked at the reset for the sequence and it made sense. That's basically all the switch does on this game.

#7 2 years ago

If you're going to check the resistance anyway, or if anyone else has the information, I'd be curious what the resistance of all four coils is:

- A-7687: Red numbered interlock relay coil
- A-6821: Yellow numbered interlock relay coil
- A-487/R20-2: P/Series relay coil
- A-489/R20-4: N/1 Point relay coil (apparently the same as A-9735 at ~14.9 ohms)

#8 2 years ago
Quoted from MarkG:

If you're going to check the resistance anyway, or if anyone else has the information, I'd be curious what the resistance of all four coils is:
- A-7687: Red numbered interlock relay coil
- A-6821: Yellow numbered interlock relay coil
- A-487/R20-2: P/Series relay coil
- A-489/R20-4: N/1 Point relay coil (apparently the same as A-9735 at ~14.9 ohms)

I believe I have found it.

During restoration of the game I lost the little brass washer that goes between my the relay frame and the coil. I replaced it with another metal washer. I removed the yellow coil from the frame and found that nonstandard washer. I removed it and replaced the coil. The number two yellow coil now no longer fires when the sequence is completed.

I'll play with it some to make sure but I manually fired the yellow number two bumper 15 times in a row and nothing happened.

Weird. Possible conductivity of the non brass washer?

Edit: That was it. I played a bunch of games and did a lot of manual bumper hits. Played correctly.

Thanks to MarkG and tfduda for helping.

#9 2 years ago

The brass washer is there to help keep the relay frame from getting magnetized. It's there because it inhibits the magnetic field to some degree on that side of the relay. A steel washer in its place might actually have the opposite effect and extend the magnetic field since steel is magnetic and brass isn't.

The theory is that the interlock relays are meant to fire when connected to the P relay (before the special is lit), but to just pass current and not fire when connected to the N relay coil (after the special is lit). In both cases current passes through the relay coil and a magnetic field is generated but only in the first case is the magnetic field strong enough to activate the interlock relay.

If that's the way it really works then it's not hard to imagine that changing the brass washer for a steel washer would affect the magnetic field and make the relay fire in both cases.

Could you verify the theory? Could you use a meter or bulb tester to see if there is voltage across the interlock relay coils after the special is active and the N relay is fired instead of the P relay? I haven't seen this approach used anywhere else.

#10 2 years ago
Quoted from MarkG:

The brass washer is there to help keep the relay frame from getting magnetized. It's there because it inhibits the magnetic field to some degree on that side of the relay. A steel washer in its place might actually have the opposite effect and extend the magnetic field since steel is magnetic and brass isn't.
The theory is that the interlock relays are meant to fire when connected to the P relay (before the special is lit), but to just pass current and not fire when connected to the N relay coil (after the special is lit). In both cases current passes through the relay coil and a magnetic field is generated but only in the first case is the magnetic field strong enough to activate the interlock relay.
If that's the way it really works then it's not hard to imagine that changing the brass washer for a steel washer would affect the magnetic field and make the relay fire in both cases.
Could you verify the theory? Could you use a meter or bulb tester to see if there is voltage across the interlock relay coils after the special is active and the N relay is fired instead of the P relay? I haven't seen this approach used anywhere else.

I will do that and see if there is voltage even when the sequence is completed. It was definitely a steel washer and I figured it had to be conducting enough to cause the coil to energize. It wasn't a lot because I could easily hold it from moving but it was enough.

I'll also see if I can find another brass washer. It was one of those dropped on the floor of the shop and rolled off somewhere.

#11 2 years ago
Quoted from MarkG:

The theory is that the interlock relays are meant to fire when connected to the P relay (before the special is lit), but to just pass current and not fire when connected to the N relay coil (after the special is lit). In both cases current passes through the relay coil and a magnetic field is generated but only in the first case is the magnetic field strong enough to activate the interlock relay.

And if your notion is true (and my understanding is somewhere in the right ballpark), the different results are presumably due to differences in properties of the P and N relay coils as these two circuits are completed, right? If so, would it be greater resistance in the N relay coil (my assumption) or the other way around?

#12 2 years ago
Quoted from tfduda:

the different results are presumably due to differences in properties of the P and N relay coils as these two circuits are completed, right? If so, would it be greater resistance in the N relay coil (my assumption) or the other way around?

Yes. Before the special when the P relay fires with an interlock relay, the current traveling through the two coils (interlock relay coil and P relay coil) is sufficient to fire both relays. After the special when the N relay fires instead of the P relay there isn't enough current through the two coils for the interlock relay coil to trip its relay but there is enough current to fire the N relay. So that implies that the N relay coil has a higher resistance than the P relay coil, since the N relay coil apparently lets less current flow than the P relay coil does.

The magnetic field strength in the interlock relay coil is also affected by the physical characteristics of the coil (number of turns, diameter, length, etc.) but none of that changes when switching between the P and the N relay coils. It's only the change in current that changes the strength of the magnetic field and the strength of the interlock relay coil.

Also interesting is that the N relay coil seems to work at the full 24 volts and whatever current that produces when operating by itself, as well as the lower voltage and current available when operated in series with an interlock relay coil.

#13 2 years ago
Quoted from MarkG:Yes. Before the special when the P relay fires with an interlock relay, the current traveling through the two coils (interlock relay coil and P relay coil) is sufficient to fire both relays. After the special when the N relay fires instead of the P relay there isn't enough current through the two coils for the interlock relay coil to trip its relay but there is enough current to fire the N relay. So that implies that the N relay coil has a higher resistance than the P relay coil, since the N relay coil apparently lets less current flow than the P relay coil does.
The magnetic field strength in the interlock relay coil is also affected by the physical characteristics of the coil (number of turns, diameter, length, etc.) but none of that changes when switching between the P and the N relay coils. It's only the change in current that changes the strength of the magnetic field and the strength of the interlock relay coil.
Also interesting is that the N relay coil seems to work at the full 24 volts and whatever current that produces when operating by itself, as well as the lower voltage and current available when operated in series with an interlock relay coil.

LOL, wow, man, you are right on the freaking money.

The resistance in the red/yellow interlock coils was about 3 ohms for all of them. The P relay about the same. The N relay is 15.7. Way, way higher resistance.

After reading your explanation the schematic makes total sense. The G relay make/break bypasses the P once the special is lit. But it brings up some other questions about this really unique circuit.

From my reading of the schematic, when the sequence is NOT complete, no special, current passes through the interlocks, they change state, and the P is fired since the G make/break is set to energize P. Then P closes and the n/o switch on P, the only switch on the relay, closes and fires N. But what confuses me is the multiple circuits to N. One circuit comes from the 1 point targets and the other through the P switch. But also current comes through the interlock coils to N when the special is lit. So from my reading there are three different ways to power N. I did meter the interlocks, special lit, and there is voltage across the interlock coils. It's not 24 volts though. And that confuses me also. Since N is much higher resistance but the current flows through the interlocks first, is the fact that N is higher resistance pulling the voltage past the interlocks since N needs more voltage to fire with higher resistance?

I have never seen anything quite like this and I'm flat amazed at your knowledge to be able to figure out how the circuit works. I didn't think anything of putting that steel washer in there because I had no idea that it would cause that much of a change in the magnetic field and cause the coil to energize. In a normal circuit it wouldn't. I wonder if Gottlieb used that circuit anywhere else. As I said, it really speaks to the engineering genius of Wayne Neyens and the guys at Gottlieb to figure this one out.

#14 2 years ago

First a clarification. I wrote 24 volts in a few places. The schematic actually says 25 volts and you might measure even more across the transformer because the wall voltage might be higher today than it was in 1963 when games might have had a low tap option on the transformer because power wasn't as consistent as it is today. None of that really matters because the games probably worked fine in a range of voltages in the mid 20s. So let's just call it full voltage instead of 24 or 25 or whatever.

So in the first case with no special, when you hit any bumper you end up with an interlock relay coil and the P relay coil connected in series across the full voltage. The switches that close to allow current to flow can be thought of as ideal and cause no voltage drop. For practical purposes that's true. So you have two coils, about 3 ohms each wired in series across the full voltage. Since they're wired in series we know the current through the pair is the same, and since their resistance is roughly equal we know that the voltage drop across each coil is about the same too. So each coil sees the current of about 4 amps (or about 24 volts/6 ohms) and a voltage of about 12 volts (since the resistances are the same the voltage across them must be the same).

The P relay coil (A-487), and both types of interlock relay coil (A-6821 and A-7687) are intended to operate in series so they work just fine at half the voltage by design. There are several other games that use coils in series like this, Mibs for example, typically when there are a bunch of targets or rollovers to hit and each one has to add the same number of points. The P relay coil fires any time any of the other targets is hit and is what awards the points as Gigi does. It saves having an extra switch on each target to just add points.

What makes Gigi interesting is that once the special is lit the P relay coil is effectively replaced with the N relay coil which has a much higher resistance as you measured. Ordinarily the N relay coil (A-489) gets the full voltage to itself whenever the P relay switch, or any other 1 point switch closes. There's no difference between the various 1 point switches. There could be a dozen of them but since they're all wired in parallel, any one or more of them closing will connect the N relay coil to the full voltage. So normally the N relay coil draws about 1.5 amps (or about 24 volts/16 ohms) at the full voltage. Again no problems, that's what it was designed for.

However, when the N relay coil fires in series with one of the interlock relay coils things are very different. The current through the two coils is about 1.25 amps (or about 24 volts/19 ohms). The voltages across the two coils are not the same since their resistances are not the same. The N relay will see most of the voltage, about 20 volts (or 16 ohms/19 ohms * 24 volts) while the interlock relay coil will see only about 4 volts (or 3 ohms/19 ohms * 24 volts).

The N relay coil can apparently operate reliably in both cases but the interlock relay coils do not work with just 4 volts and 1.25 amps. So they're deliberately failing to operate to avoid unsetting the special until the ball drains. They do consume power and will get hot if left on, but they just don't get enough power to actually trip the interlock.

#15 2 years ago

That is a great lesson and I really appreciate the explanation. It's just amazing that all this occurred due an replacement of a part I thought nothing of but which caused all this. I'd totally forgotten I replaced that washer until I took it apart this afternoon and found it. Since I had never before seen coils set up in series like this I didn't think the composition of the washer really mattered. I was thinking more of spacing than magnetism.

You learn something every day

So from the schematic with the specials not lit, bumper hits cause the interlocks to change state and the P to fire. The P switch then fires N to move the reel. The N is also fired directly by the slings and any other standup switches.

With the specials lit P is bypassed for bumper hits and the voltages goes through the interlocks, but not enough to fire the interlock coils but fires N. And the other circuit from the stand ups directly fires N.

Slick

#16 2 years ago

I have a spare washer or two and could mail them to you.

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