(Topic ID: 312510)

Magic city with strange magic

By BurtronRaoolala

10 months ago


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mcsch (resized).jpg
target relay (resized).PNG
Motor Run (resized).PNG
Magic city (resized).PNG
Armature in (resized).png
Armature out (resized).png

#1 10 months ago

Hi,

I’m working on a 1967 Williams Magic City. It was in storage for 25 years. So it is dirty and grimy but is a diamond in the rough. So I have cleaned every switch, tested every coil, fixed a couple of bad solder connections etc. So it is looking pretty good but I have a problem that I cannot seem to solve.

If I plug the machine in and hit the left flipper button, the playfield and the back glass light up perfectly. The lock relay is engaged and the game over relay is activated just like it is supposed to. So far, so good. However, when I start a game, the motor keeps running. Yes, a common problem but here is the weird thing: the entire startup sequence completes. Everything does exactly what it is supposed to, the score reels zero out, all the zero switches on the score reels are open, the reset relay fires and all the Switches that control the m,a,g,i,c,c,I,t,y targets reset perfectly. Everything on the playfield operates perfectly. But the motor won’t turn off.

I have a schematic and have checked every switch for proper operation and settings. Every switch on the motor cams are clean and set correctly including the home switch. But the motor continues to run. The last step of the startup process is the outhole kicker pushing the ball into the shooter lane. All of this happens perfectly. But the motor won’t shut off!

I have tried everything that I can think of and am out of ideas. The ball counter unit works perfect, the match component works perfectly, everything scores perfectly. Like I said, everything has been meticulously cleaned and tested. There is no bonus unit on this game as it doesn’t have a bonus feature. Also should note, the coin mechs are gone on this machine so nothing plugged in to the Jones plug for the coin mechs. It is set for free play and the machine worked fine when it was stored those many years ago.

Any ideas? Something must be still sending power to the motor. Should I take the wire harnesses apart and look for wires touching or something? Or do you think I have a cold solder joint somewhere that I just cant see? How can I test for this? I have a dmm and know how to use it…….

Thanks for your comments, questions, and suggestions. I’m starting to think this machine is haunted.

#2 10 months ago

Following the schematic, systematically block a switch in a path that powers the score motor (with card stock) until you find the culprit.

#3 10 months ago

90% of time it is the score reels doing this. Take each reel out and clean contacts on the zero switches. Sometimes just pressing on switches at reel will stop the score motor.
I had an old Williams where the score motor armature was stuck causing the motor to overrun the home position. Now I always put a drop of oil on SM armature when I get an new machine. Putting strip of paper in Motor Run, contact top of index stack will verify.
Here is picture:
Armature in (resized).pngArmature out (resized).png

#4 10 months ago

The armature is not stuck and is operating correctly.

I’m confused about your comment regarding the score reels. When the reel is zero, all the switches are open. My documentation shows that all switches are supposed to be open when reels are on zero. Is this incorrect? Do different years operate differently? Btw, all the score reel switches are clean. I guess I could close all the zero switches and see if the motor stops. If this is the fix I’m going to feel pretty dumb. But happy!

Thanks for your suggestions.

#5 10 months ago
Quoted from BurtronRaoolala:

The armature is not stuck and is operating correctly.
I’m confused about your comment regarding the score reels. When the reel is zero, all the switches are open. My documentation shows that all switches are supposed to be open when reels are on zero. Is this incorrect? Do different years operate differently? Btw, all the score reel switches are clean. I guess I could close all the zero switches and see if the motor stops. If this is the fix I’m going to feel pretty dumb. But happy!
Thanks for your suggestions.

You are right about the reel switched. Guess I got confused. I am looking at the Magic City schematic and there are not too many things that power the score motor. Need to see which one is the one powering the motor. Follow the O-G (orange-green) wires and isolate with paper.
Magic city (resized).PNG

#6 10 months ago

Ok, cool. I think the zero switches on the score reels do close on a multi player game but not the single players. I also have a Williams Touchdown (about same era as Magic City) and it opens all zero switches on zero as well.

Yes, per the schematic, I believe it only shows 4 possible circuits that power the motor. I have located each switch and did the cardboard thing and the motor still runs. I MUST be missing something and/ or the schematic is not showing me everything. I also checked each switch on each relay involved in the circuit to see if any wire or wire stubs were touching but everything looks very good. I don’t know, I might be chasing my tail here….again!

#7 10 months ago
Quoted from BurtronRaoolala:

Ok, cool. I think the zero switches on the score reels do close on a multi player game but not the single players. I also have a Williams Touchdown (about same era as Magic City) and it opens all zero switches on zero as well.
Yes, per the schematic, I believe it only shows 4 possible circuits that power the motor. I have located each switch and did the cardboard thing and the motor still runs. I MUST be missing something and/ or the schematic is not showing me everything. I also checked each switch on each relay involved in the circuit to see if any wire or wire stubs were touching but everything looks very good. I don’t know, I might be chasing my tail here….again!

There are 6 paths for power. Do not discount the coin relays. Look at Target, Outhole and Reset relays and make sure they are not energized. Paper in Motor Run? See if unplugging the coin door connector stops the score motor. Often people hacking in free play do bad things.
Motor Run (resized).PNGtarget relay (resized).PNG

#8 10 months ago

Yes, I have seen some hacked up messes but this is not that. I’ve owned this machine for over 30 years and it worked fine when it was put in storage a long time ago.

As I mentioned in my original post, there are no coin mechs so no plug from the coin mechs. The target, outhole, and reset relays are not energized at the end of the startup sequence. I’ve looked at the switches in each aforementioned relays and they are all clean and adjusted correctly. And yes, paper in the motor run has no effect. Motor still runs!

I’ve spent an embarrassingly large number of hours on trying to solve this which is bad enough but added to that is the fact that I am a software engineer and fully understand how to solve logic problems and how to divide and conquer. Even worse, I owned a custom computer business for 15 years back in the day and have built thousands of computers. Crazy.

I’m almost convinced that there must be a short somewhere in the circuits that run the motor. The machine was stored for a time in a barn (Southern California so no cold weather or temp extremes) and was home to a couple of mice families. Although they don’t appear to like to chew the wires with the cloth insulation, they may have chewed on the wires with the plastic insulation. I might take all the wire harnesses apart and look for any damage. There is a big fat gremlin in this machine and thus far, it has escaped my efforts.

Thanks again for your comments.

#9 10 months ago

With the game reset and the score motor still running, try this: Unplug the Motor Service Jack (Red circle) This should open the circuit to the score motor. If the motor stops when you remove the jack, you'll know that opening that path will stop the motor. So one of the switches in that (blue path) must be closed. Once they are all open the motor should stop just like when you unplugged the jack.

I would suspect the 25c and 10c relays first. Even though you don't have coin mechs ,those relays are still part of the circuit (unless somebody removed the relays as well). Also even though a switch looks open, there's no guarantee that it is. I've seen switches with the little plastic bushing missing that were shorted together by the switch stack screw, so anything's possible. Keep checking all those switches in the blue path, even if you have to desolder one end to be sure.

Now if the motor keeps running after you unplug the service jack, then you've really got a problem.

mcsch (resized).jpg

#10 10 months ago

Have you carefully looked at all the tabs on the back of each of those switches that drive the motor? If they were touching, putting paper between the contacts wouldn't matter. You could even unsolder the O-G wire on each of those switches and see what happens.

If the tabs aren't shorted, and you've put paper between the contacts of all 6 switches at the same time and the motor still runs, you might have a short between the O-G and YEL wires. I'm not sure there's a logical way to pinpoint such a short - you'll just have to very carefully examine all the O-G wire and see if you notice anything suspicious.

#11 10 months ago

If the reset relay de-energizes but the motor keeps running I’d check the M-B switch on the index cam. Maybe it’s very tight and not opening long enough to stop the motor?

Also when you cut the power, carefully watch to see if any relay de-energized that shouldn’t be energized.

The score motor doesn’t start running until the reset sequence — to me that eliminates any persistent short scenario.

#12 10 months ago

Thanks for all the good suggestions. Very much appreciated.

Edednedy, when I remove the motor service jumper, the motor does stop. There is a 25c relay still in the game and like you, I highly suspect something fishy with it. The top switch on it is a flip flop switch and both sides of it appear to make the motor run. I think I will eliminate it from the circuit and see what happens. If after eliminating everything that makes the motor run and it stills does, I fear your last statement may be true.

Paulace, yes I have done that as well. I have spent hours examining the tabs and the wires themselves to attempt to see anyplace that they may be shorted. I think I will take your suggestion and unsolder the O-G wire on each switch and observe what happens. If that still doesn’t tell me anything, then there must be a short between the O-G and Y wires as you say. Finding that would not be easy or fun.

Dr_nybble, I would agree with your last statement however if I plug in the game and turn on the power via the left flipper switch, everything is right. But if I start a game, it will go through the reset cycle completely, but after kicking the ball out, the motor still runs. If I unplug it then turn on power via the flipper switch again, now the motor runs before starting a game. There must be a short somewhere or a stuck switch or a switch that appears open but really is not.

Thanks again for the great ideas and suggestions. I’m planning on digging back into this today and getting it solved while I still have a few hairs left in my head.

#13 10 months ago

If it runs after power cycle then it may be a latched relay.

You said that it will keep running if you turn the machine off while in this state. If you rotate the score motor by hand to its initial position and then power the machine on, does it run?

Does the target relay energize? The target relay can cause the score motor to run, but only after a game has been started.

#14 10 months ago

Ok, finally got this thing to start. The problem was pretty unique. Turns out, on the index switch stack, the two switches on the top were reversed which is no big deal except that I was reading the schematic and assuming the top switch was the one I was interested in. Turns out it was the next switch down.

That alone isn’t the problem however. Turns out, that switch was missing one half of the insulator between itself and the top switch. That is why the motor never stopped.

When I pulled this game out of storage and did my initial cleaning, I remember seeing one half of an insulator laying in the bottom of the machine. I remember telling myself that this was going to bite me in the butt. And so it did!

I want to once again thank all the folks that got me on the right track. I still have some issues with this game but I think I can get her back to working and playing correctly now. Thanks!

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