Gottlieb Solved "300" (Gottlieb, 1975) Mystery Score

jay3489

Pinball Wizard
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Favorite Pinball Machine
Moulin Rouge
Been working on a 300
Got just about all the bugs worked out except for one

The Mystery Score.


When the ball lands in the yellow saucer you get
500 points and 1 bonus

or
1,000 points or 2 bonuses
or
1,500 or 3 bonuses

Supposed to be totally random

Mine keeps giving 500 points and 1 bonus
It never changes.


Part of the circuit includes a capacitor, diode and wire round resistor on a jones plug

All three components check good.

These 3 components are tied into a N/C "I " relay

When that relay is activated it opens and its all over the place when it releases.

Anywhere from 2 to over 30 seconds.

It appears to be held in place from a small stray voltage, probably from the capacitor.

If anyone could explain to me how this circuit works and offer any suggestions I would greatly appreciate it.
 
Solution
I replaced the cap today
After turning the machine on, the “I†relay was working properly for a short time
It was releasing in about a second

Then it went back to holding closed for a much longer time

I took the entire relay apart
Cleaned up everything, figured maybe something was binding

Even installed tighter return spring

Still no luck

Then I came up with an idea

I put a thin piece of felt on the armature so now when it pulls in, its to enough open the switch but leave a tiny gap

Now it’s working perfectly every time . Releases in about a second every time

I have no idea what was causing this to stick , but my workaround works great

You can see the white piece of felt sticking out behind the...
After doing some more work on the machine, I found the problem with Mystery Bonus

It was some dirty switches on the score motor

The Mystery Bonus is controlled by 2 switches on the score motor

But I still have a problem with the “I” Add Bonus Delay relay

If I unplug the circuit, capacitor , diode resistor, everything is working because the relay does not engage

When I plug it back in the Add Bonus Delay will sometimes hold in for well over 30 seconds

Even if I turn the machine off it will still hold for a while

If I unplug the circuit it releases

It appears that the capacitor is holding it in until it drains

So my question now is why is the Add Bonus Delay relay holding in so long?

I would think it should reset in a second or so after being energized
 
Looks like an interesting variation of Gottlieb's "Atlantis" I used to own. Same year.

I never had to replace one of the caps, though-- only clean contacts.

There's a guy who visits here off and on who could help sort this out, if you can catch him.
 
I’m going to try and change the cap and see what’ happens

Actually the machine runs better with that time delay module unplugged

I’m not really sure what purpose it serves
 
You see that type of delay circuit in machines that have a spinning target bonus ladder feature.
When the spinning target switch closes it pulses the J relay, then the J relay will pulse the I relay.
When the I relay is held in from its pulse it’s nc switch opens the circuit to other bonus scoring targets so that the bonus unit advance coil doesn’t rapid fire.
Consistent charging of the capacitor is needed for proper timing release of the coil, so I agree with changing it is needed.
If you can’t get the timing down to 1-2 seconds for coil release, play it without the delay.
 
Thank you very much for a great explanation

I’ll be replacing the cap today and hope for the best

After all it’s over 40 years old
 
I replaced the cap today
After turning the machine on, the “I†relay was working properly for a short time
It was releasing in about a second

Then it went back to holding closed for a much longer time

I took the entire relay apart
Cleaned up everything, figured maybe something was binding

Even installed tighter return spring

Still no luck

Then I came up with an idea

I put a thin piece of felt on the armature so now when it pulls in, its to enough open the switch but leave a tiny gap

Now it’s working perfectly every time . Releases in about a second every time

I have no idea what was causing this to stick , but my workaround works great

You can see the white piece of felt sticking out behind the armature on the enclosed pix


IMG_5923.JPG
 
Solution
Nice work, Jay!

Honestly, that kind of thing is why I loved working with EM's. As in, a good portion of this stuff you can just figure out using common sense, trial & error, etc. Not every solution has to be 'by the book.'
 
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