Gottlieb Grand Slam (Gottlieb, 1972) Help me out dudes!?

teamhex

I PwN nOoBs
Joined
Mar 24, 2009
Messages
52
Reaction score
5
Points
10
Favorite Pinball Machine
South Park
Well Iv been for the last 2 weeks working on a pinball machine I bought from down the street. I'm going to post all the pics below in order as I took em. Well the basic story is, I played it when I bought it and everything seemed to work. Now the reels don't reset at the beginning of the game, that's not the main issue though. My dad was jacking with the power button(sounded like he turned it on and off to fast) now it wont turn on...at all. Also while I was playing my flippers felt a bit weak, and made a loud hum if I held the buttons down. Im 21 and dont know jack about this old technology. If this were a computer im sure I would be able to easily trouble shoot this.

Gottlieb Grand Slam 1972


100_3781.jpg


100_3782.jpg


100_3780.jpg


100_3779.jpg


100_3775.jpg


100_3773.jpg


100_3774.jpg


100_3806.jpg


100_3807.jpg


100_3808.jpg


100_3809.jpg


100_3812.jpg


100_3814.jpg


100_3815.jpg


100_3819.jpg


100_3820.jpg


100_3822.jpg


100_3823.jpg


100_3824.jpg


100_3826.jpg
 
I often hear things in the house that convinces me that there is someone/thing there - possibly hiding. I have to seach through the place room by room to convince myself all is well. It does my bloody head in :(

And once my mind is 'tuned' to the 'frequency' I hear it more and more. There's only one way to sort it out, turn the system up and drink more :D
 
Well like I said dudes, the left flipper was making tons of noise, and now has quieted down big time. Its still weak though, and the right still makes noise. My dad was saying he thinks the transformer may not be giving full power in each rail(more like line, im a computer guy, so im using the word "rail" here).
 
I still think those weak flippers are due to a solenoid going bad! yester-years solenoids are not as well-built as todays are! I'd replace it before it fries, possibly taking something else with it! weak flippers are almost always caused by a bad solenoid or a sticking rod (the rod that travels thru the actual solenoid) causing those lights to dim as the pin tries to draw more power to get the flipper to work. and just read the directions that came with your multimeter, it'll explain how to perform the diode test, (or just google it!) but PLEASE make sure the thing is unplugged and there is no residual power left on the board! Does it even have a board or is it all just switches underneath with relays? Depending on how old it is you may not even have any circuit boards in it at all.
 
I still think those weak flippers are due to a solenoid going bad! yester-years solenoids are not as well-built as todays are! I'd replace it before it fries, possibly taking something else with it! weak flippers are almost always caused by a bad solenoid or a sticking rod (the rod that travels thru the actual solenoid) causing those lights to dim as the pin tries to draw more power to get the flipper to work. and just read the directions that came with your multimeter, it'll explain how to perform the diode test, (or just google it!) but PLEASE make sure the thing is unplugged and there is no residual power left on the board! Does it even have a board or is it all just switches underneath with relays? Depending on how old it is you may not even have any circuit boards in it at all.
Its from 72 man, from what I can see, its a ton of relays and contact switches. A transformer and tons of other random things.
 
Found a site which may help you out: http://www.pinrepair.com/em/

faralos said:
PLEASE make sure the thing is unplugged and there is no residual power left on the board!

Listen to faralos. A dodgy power supply is nothing to mess with. He's also right in that the flipper solenoid is drawing too much current.

Oh, and just in case you haven't read the article(s) above yet - DON'T LUBRICATE ANYTHING!!!!! Especially the solenoid rods. Throw that WD-40 aside - you'll likely set fire to your new acquisition.

It looks like early pinnies used 6V AC to power the lights and 24-30V AC to power the solenoids. NO DC! This surprised me, but does simplify the power supply a lot.

Out of all the components, though, the transformer is likely to have weathered the age better, provided the primary coil winding insulation has held up. The primary is more vulnerable as it is exposed directly to mains voltage and inrush current when switched on (and then again when the electric field and induced magnetic field in the core collapses as it is switched off).
[EDIT] The author above concurs - he says out of ~300 pinnies he's fixed, only one had a bad transformer, and it was a melted blob of goo.

faralos said:
Does it even have a board or is it all just switches underneath with relays? Depending on how old it is you may not even have any circuit boards in it at all.

teamhex said:
Its from 72 man, from what I can see, its a ton of relays and contact switches. A transformer and tons of other random things.

Sounds like the underside of the playfield is the board. So where, then, is the transformer and other power supply components? At the rear on the bottom of the cabinet?

In those days things were built to last much more so than today, but solenoids are particularly vulnerable because they move.

None of it is random - everything was carefully put there for a particular purpose. I think you have established that the switches and relays work - they're the least of your troubles.

Lets not forget that 3 years before that thing was made, the same generation of components sent people to the moon and back several times. Apollo 11 almost failed to return because Buzz Aldrin broke off the switch controlling the pyro-bolt which separated the lander and return capsule with his backpack on the way out the door (must have been a really fun moon walk - they were later saved by a NASA pen which just fit in the switch hole allowing them to close the circuit), and 13 because the wrong size bolt was installed in an oxygen tank stirrer - human error each time. Military spec components were used, but they still aren't a whole lot better than industrial spec, and your pinball machine never had to survive a space launch or mach2 at 100,000 feet!

elton said:
and I just thought it was the noises in my head! :grin:
Ha! Elizabeth Taylor swears she could hear voices due to the fillings in her teeth when she drove past a local radio transmission tower. Unfortunately there's nothing to provide anything like a tuned circuit in dental amalgum and unconductive bone like teeth....

phoenixx said:
Teapots on electrical stoves, but then i think many things would do that if the circumstances are right,...
Love the teapot story, and I'm sure it happens from time to time - but without an amplifier you'd have to be pretty bloody close to the transmitter and in a very quiet place. I wonder if changing the amount of water in the kettle allowed her to change channel!

My friend built a crystal set and it's loud and clear with a matched impedance earpiece, but through an 8 Ohm speaker you could barely hear it (but you could hear it).

teamhex said:
My dad was saying he thinks the transformer may not be giving full power in each rail.
Please clarify. What voltage rails are available - 6VAC and 30VAC?

If you have the manual and circuit diagram - attach them here and give us a squiz. Also need to know your mains voltage and frequency if it's not on the diagram.

Also - where are you at? What has changed that the flipper doesn't buzz anymore and the 'staged' failure no longer occurs?
 
Last edited:
Oh, and just in case you haven't read the article(s) above yet - DON'T LUBRICATE ANYTHING!!!!! Especially the solenoid rods. Throw that WD-40 aside - you'll likely set fire to your new acquisition.
Yeah, I read that so im not going to lube anything.

It looks like early pinnies used 6V AC to power the lights and 24-30V AC to power the solenoids. NO DC! This surprised me, but does simplify the power supply a lot.
You'd think, but the transformer is working, im just not sure if its fully working. Its between there and what powers most of the components except the back light.



Sounds like the underside of the playfield is the board. So where, then, is the transformer and other power supply components? At the rear on the bottom of the cabinet?
Its at the rear almost under where the backboard is at. It hums and seems to give power to the backboard, but nothing else.

None of it is random - everything was carefully put there for a particular purpose. I think you have established that the switches and relays work - they're the least of your troubles.
Except some homemade wires someone put in to start the game by pushing the button on the front(its not connected right now) That and my play counter doesn't move its stuck at 83,950.


Lets not forget that 3 years before that thing was made, the same generation of components sent people to the moon and back several times. Apollo 11 almost failed to return because Buzz Aldrin broke off the switch controlling the pyro-bolt which separated the lander and return capsule with his backpack on the way out the door (must have been a really fun moon walk - they were later saved by a NASA pen which just fit in the switch hole allowing them to close the circuit), and 13 because the wrong size bolt was installed in an oxygen tank stirrer - human error each time. Military spec components were used, but they still aren't a whole lot better than industrial spec, and your pinball machine never had to survive a space launch or mach2 at 100,000 feet!
Makes me feel better, but I still don't know much about this technology. My dads calling in a favor, if that doesn't work im just going to swallow my pride and pay someone to get it working.

Please clarify. What voltage rails are available - 6VAC and 30VAC?
25volt 15amps, 6 volt 10 amp, 6 volt 7 1/2 amp. How I remember that is insane, lol. O any the fuse for the power cable is a 5 amp slow blow.


If you have the manual and circuit diagram - attach them here and give us a quiz. Also need to know your mains voltage and frequency if it's not on the diagram.
Man I would, but the schematic is so old its almost falling apart, like it was the declaration of Independence. Maybe i can find a PDF version online. Or if you guys are better at search its a "Gottlieb grand slam 72". Theres a 50's version Gottlieb made but its different.

Also - where are you at? What has changed that the flipper doesn't buzz anymore and the 'staged' failure no longer occurs?
Im sorry, it made it sound like it was working again. When we played the 25 games on it(before failing), the left flipper near the end quit buzzing as loud. It got quiet like what I would think it should sound like.
 
Last edited:
odd that it would go from buzzing loudly to being quiet! that alone would or should raise alarm bells in your head! why'd it suddenly get quieter? now you must find out if anything else is possibly drawing that current away from the flipper soleniod, making it go quieter. I know all this sounds incredibly daunting, what with all of us giving you all these possible reasons why it's not working correctly, but welcome to the wonderful world of pin diagnostics! Without it in front of us, the best we can do is hypothetical reasonings, but you bought it knowing it would need work, that's half the fun of restoring something anyway, whether it be an old car, or a pin, something always needs to be fixed/cleaned/adjusted, just be glad we are all here to lend a (virtual) helping hand. And keep us informed of your progress, btw the paint job looks great!
Have fun with it (wish I had one to 'toy' with)
 
teamhex said:
My dads calling in a favor, if that doesn't work im just going to swallow my pride and pay someone to get it working.
Awwww! C'mon man, you know you can do this! Anyway it will cost a stinking fortune!!!! Parts _and_ labour. Jeez!

Got another link for parts - couldn't find any doco on the web, though... Perhaps if you e-mail these folks they can get you some inexpensive replacement parts and maybe even more doco.

http://www.pbresource.com/your1st.html

If you're running on 110Volts 60 Hz then that transformer isn't having to work very hard to step down to your operating voltages, personally I'd feel pretty comfortable that it is ok. It hums - that's cool, so do the ones on towers in my neighbourhood.... thats' just the coils trying to move at right angles to the electric field being generated within them. Since they can't, a corresponding Magnetic field is induced in the iron core, circles around and induces an electric field in the secondary coils, and since _they_ can't move, they in turn induce a current of the same frequency but at a different voltage depending on the ratio of coil turns between primary and secondary. But there is a mechanical force being applied at a specific frequency - humming in a TXr is ok. Not ideal but ok.

OK, so you're chucking in 110VRMS @ 5amps max, or 550Watts RMS. 25 volts can't kill you unless you've got heart troubles, but it will kick you like a mule if you let it. The 6V 10A and 7.5A light circuits chew up 105W RMS max, and the solenoid circuit is 25V @ 15A or 375W RMS = 480W RMS, so your individual circuit fuses will blow well before your slow burn mains fuse does.

The EM reels will be powered by the 25V solenoid circuit, so it's no surprise the scoreboard is frozen.

If you really want to test that transformer, you need to test each secondary under load. Since the backlight is working (and I'm assuming one of the 6V circuits is powering the backlight), then you've got a circuit for at least one of them to get an AC VM reading while the lights are on.
For the other circuits lets choose half the fuse value of current -
Ohms law: V=IR, R=V/I so to pass 7.5A at 25V (187.5Wrms) we need a total circuit load resistance of 4 Ohms rated at 200W (and since it's RMS -0.707x- this gives us an even greater margin of safety).

However, to test it, we're going to 'short' the secondary across this resistor and measure the AC voltage across said secondary/resistor, and since it's in parallel with the rest of the circuit lets double it, so a Power or Load Resistor with a value of 8 Ohms and a Power rating of 200W ought to cover it for the case that the 25V circuit is open-circuit (passing 3.75A through 8 Ohms) or at 2/3 max load (10A or 2.5 Ohms circuit impedance in parallel with 8 = 40/19 Ohms) passing just under 12.5A total. We can safely assume it's not short-circuited or you would have already lost your 15A fuse already so 2/3 max load is an overestimate - it's probably open.

Actually before doing this it's probably better to test each secondaries AC voltage and current as is. To test current you have to have an (AC) ammeter in series with the circuit under test. This will give you an idea of what's going on down the line. If nothing currently works then you've probably got an open circuit doen the line, hence 25 volts at 0 amps - then you can use the 4 Ohm 200W Power resistor to better test the secondary under load.

Clear as mud? Sorry it's very late and I'm having waking nightmares about being back at school again. To make it easier, disconnect the secondary circuits from the rest of the machine - test the 25V circuit through the fuse and 4 Ohm 200W(minimum) power Resistor in isolation (7.5A).

Then either the 6V 10A or 7.5A circuits through the fuse and a 2 Ohm 100W Power resistor (3A).
 
whew! nothing like an Electrical Engineer to clear things up! :)Hope you got all that, it sounds way worse than it actually is once you begin to understand electrics a bit (more than you do atm) Meecro is dead on! listen to anything he says as he knows way more than I ever did with electrical troubleshooting, I am old school (if it broke I could trace and find the problem, but I realized I know next to nothing after reading (ok, stumbling my way through) his post:p
 
Actually it's much more complicated. That's just Ohms Law which only works accurately for DC circuits with no capacitative or inductive reactance (yr 7 maths).

To do it accurately involves complex numbers and frequency-based mesh analysis (yr 12-uni maths and a bastard little variable called omega).

I can't remember _any_ of the latter - never really had to use it (used to be soooo good at that crap though).

So I've used the former and thrown in a great blob of margin-of-error. Still works ,though.

And be careful poking your digits near the live transformer - stay waaaaaay away from that primary. 25 Volts decoupled by the transformer from the mains can't kill you, but the primary can.
 
I never was but an amateur and I don't know much about pinball electronics, but couldn't the current to the flippers be measured at the flipper button contacts? What about connecting the triggers through an ampmeter? These are simple series contacts. And couldn't the other bumper solenoids, slingshot solenoids be checked by pulling one of the wires and completing the circuit though the meter in series? With all of these circuits, you would set the meter to amps.
Use alligator clips to connect the circuit.

Doesn't the manual have the voltage and amperage ratings for specific components listed? If not, you can also check for the ratings printed on the specific solenoids and relays if present.

I'd definitely check the contacts at the flipper buttons for "the buzzing flipper" which I'm guessing are simple leaf contacts, just two strips of copper. Set the meter to Amps and connect the two contact leaves through the meter.
Check those contacts for oxidation and try sandpapering them lightly if oxidation is present, or replace them if they are too corroded.

Bad electrolytic capacitors are often spotted by bloating. They should look perfectly cylindrical with no bulging on the flat top. Also look for melted goo oozing from the electrolytic capacitors or around their mounting point on a circuit board. If you see bulging or oozing, replace them. Other capacitor types like bad disk capacitors are harder to spot, though they may appear to be charred or burnt or show blotches of discoloration from heat damage, especially on any insulation wrapped around the capacitor's leads.
 
if I remember correctly those older solenoids (by now anyways) didn't have the printed paper that's on those newer ones stating ohms or currents or anything, heck they may not even have any wrapping on them at all! and yes I forgot, those flipper contacts may just be corroded or worn, causing that buzzing. If they are copper they may be corroded to the point where they aren't making good contact resulting in a weak flipper( and creating that buzzing sound). Invest in a small fiberglass brush (try a Radio Shack or computer store) for cleaning all your contacts, the gentle fiberglass brushes will clean dirt and corrosion off of the contacts without actually scraping them. Thin emery boards work too for cleaning in between the thin contacts (drop targets and pop bumper contacts are these types) or if nothing else use ultra fine sandpaper (1000-1200 range) wrapped around a popsicle stick just remember to blow clean all the sandpaper dust! a can of contact cleaner will only clean it a little, they are good for keeping it clean, but in your case sanding the contacts will work better.
have fun with it! while it may seem like a lot of work (what good hobby isn't?) it'll all turn out good in the end, and you will be more proud, knowing that you did the work yourself, rather than just handing it over to someone else to do (and a heck of a lot less expensive, too) Pinball mechanics (by me anyways) charge upward of $100/hr to fix pins. I live in the Eastern US, and they are few and far between so they can charge almost anything and get away with it. But hunt down the manual for it, it'll help so much (they have schematics in them for all the wiring and electronic stuff and basic troubleshooting/bookkeeping) good luck, keep us posted on your progress!
 
Awwww! C'mon man, you know you can do this! Anyway it will cost a stinking fortune!!!! Parts _and_ labour. Jeez!

Got another link for parts - couldn't find any doco on the web, though... Perhaps if you e-mail these folks they can get you some inexpensive replacement parts and maybe even more doco.

http://www.pbresource.com/your1st.html

If you're running on 110Volts 60 Hz then that transformer isn't having to work very hard to step down to your operating voltages, personally I'd feel pretty comfortable that it is ok. It hums - that's cool, so do the ones on towers in my neighbourhood.... thats' just the coils trying to move at right angles to the electric field being generated within them. Since they can't, a corresponding Magnetic field is induced in the iron core, circles around and induces an electric field in the secondary coils, and since _they_ can't move, they in turn induce a current of the same frequency but at a different voltage depending on the ratio of coil turns between primary and secondary. But there is a mechanical force being applied at a specific frequency - humming in a TXr is ok. Not ideal but ok.
Yeah I was looking to buy a lockdown bar from pbreasoure, the ordering is a bit odd, lol. So you dont think its the transformer? Is there such thing as a secondary power supply? Im getting power too my back board, but nothing else. At least thats what it feels like.

OK, so you're chucking in 110VRMS @ 5amps max, or 550Watts RMS. 25 volts can't kill you unless you've got heart troubles, but it will kick you like a mule if you let it. The 6V 10A and 7.5A light circuits chew up 105W RMS max, and the solenoid circuit is 25V @ 15A or 375W RMS = 480W RMS, so your individual circuit fuses will blow well before your slow burn mains fuse does.

The EM reels will be powered by the 25V solenoid circuit, so it's no surprise the scoreboard is frozen.

If you really want to test that transformer, you need to test each secondary under load. Since the backlight is working (and I'm assuming one of the 6V circuits is powering the backlight), then you've got a circuit for at least one of them to get an AC VM reading while the lights are on.
For the other circuits lets choose half the fuse value of current -
Ohms law: V=IR, R=V/I so to pass 7.5A at 25V (187.5Wrms) we need a total circuit load resistance of 4 Ohms rated at 200W (and since it's RMS -0.707x- this gives us an even greater margin of safety).

However, to test it, we're going to 'short' the secondary across this resistor and measure the AC voltage across said secondary/resistor, and since it's in parallel with the rest of the circuit lets double it, so a Power or Load Resistor with a value of 8 Ohms and a Power rating of 200W ought to cover it for the case that the 25V circuit is open-circuit (passing 3.75A through 8 Ohms) or at 2/3 max load (10A or 2.5 Ohms circuit impedance in parallel with 8 = 40/19 Ohms) passing just under 12.5A total. We can safely assume it's not short-circuited or you would have already lost your 15A fuse already so 2/3 max load is an overestimate - it's probably open.

Actually before doing this it's probably better to test each secondaries AC voltage and current as is. To test current you have to have an (AC) ammeter in series with the circuit under test. This will give you an idea of what's going on down the line. If nothing currently works then you've probably got an open circuit doen the line, hence 25 volts at 0 amps - then you can use the 4 Ohm 200W Power resistor to better test the secondary under load.

Clear as mud? Sorry it's very late and I'm having waking nightmares about being back at school again. To make it easier, disconnect the secondary circuits from the rest of the machine - test the 25V circuit through the fuse and 4 Ohm 200W(minimum) power Resistor in isolation (7.5A).

Then either the 6V 10A or 7.5A circuits through the fuse and a 2 Ohm 100W Power resistor (3A).
Sounds like you'd be right, but that 5 amp fuse blew and not the other ones. It was because someone had a 3.5 amp fuse in there, but still, lol. Ill go ahead and try that, Iv got to print it out though. Thanks mate. I thought amps are what killed out not voltage. Isn't it anything about 8+ amps can kill you?




odd that it would go from buzzing loudly to being quiet! that alone would or should raise alarm bells in your head! why'd it suddenly get quieter? now you must find out if anything else is possibly drawing that current away from the flipper soleniod, making it go quieter. I know all this sounds incredibly daunting, what with all of us giving you all these possible reasons why it's not working correctly, but welcome to the wonderful world of pin diagnostics! Without it in front of us, the best we can do is hypothetical reasonings, but you bought it knowing it would need work, that's half the fun of restoring something anyway, whether it be an old car, or a pin, something always needs to be fixed/cleaned/adjusted, just be glad we are all here to lend a (virtual) helping hand. And keep us informed of your progress, btw the paint job looks great!
Have fun with it (wish I had one to 'toy' with)

It is weird, but I still don't know what it is. I really don't know what my next step should be. I appreciate the help, but like computers its hard to figure something out for the most part if its not in front of you.
 
Last edited:
if I remember correctly those older solenoids (by now anyways) didn't have the printed paper that's on those newer ones stating ohms or currents or anything, heck they may not even have any wrapping on them at all! and yes I forgot, those flipper contacts may just be corroded or worn, causing that buzzing. If they are copper they may be corroded to the point where they aren't making good contact resulting in a weak flipper( and creating that buzzing sound). Invest in a small fiberglass brush (try a Radio Shack or computer store) for cleaning all your contacts, the gentle fiberglass brushes will clean dirt and corrosion off of the contacts without actually scraping them. Thin emery boards work too for cleaning in between the thin contacts (drop targets and pop bumper contacts are these types) or if nothing else use ultra fine sandpaper (1000-1200 range) wrapped around a popsicle stick just remember to blow clean all the sandpaper dust! a can of contact cleaner will only clean it a little, they are good for keeping it clean, but in your case sanding the contacts will work better.
have fun with it! while it may seem like a lot of work (what good hobby isn't?) it'll all turn out good in the end, and you will be more proud, knowing that you did the work yourself, rather than just handing it over to someone else to do (and a heck of a lot less expensive, too) Pinball mechanics (by me anyways) charge upward of $100/hr to fix pins. I live in the Eastern US, and they are few and far between so they can charge almost anything and get away with it. But hunt down the manual for it, it'll help so much (they have schematics in them for all the wiring and electronic stuff and basic troubleshooting/bookkeeping) good luck, keep us posted on your progress!
I sanded both flipper contacts with like 900grit sandpaper so you would think both would have done the same thing.
 
Last edited:
teamhex said:
Isn't it anything about 8+ amps can kill you?
You're right it's current not voltage that kills. 65 milliamps can kill you. But it's the pressure (voltage) and resistance (MegaOhms for skin) that determines the current. I=V/R.

teamhex said:
Is there such thing as a secondary power supply?
Since your pinball machine was never expected to go into space or operate far from help, there will be no backup power supply (that's what repair technicians are for!).

Your next step is to figure out where your open (break in the) circuit is for each non-operating circuit - power off.

This will be way easier if the transformer secondary's are disconnected.

Now it is complicated a bit by the fact that it is a completely AC circuit. Capacitors can be happily in-series and act effectively like a time-delayed wire (delay dictated by capacitance and in-series resistor). If there is a capacitor in-series with the circuit that will blow the DC resistance measuring technique (2) below out of the water completely.... You'll get a (very) brief reading and then an open circuit. I've never used it but you can do an AC circuit continuity test with a 1.5V battery in series with an 8 Ohm speaker. Use this to test as in (2). If you hear a 'click' throught the speaker then you have a closed circuit.

Use sleepy's method of checking caps by eye. I'd replace all electrolytics anyway (they age badly but they're cheap).

1. If there are caps in series with the main circuit you're going to have to check the continuity of each (non-capacitor) component and wiring separately or use the battery/speaker technique above. If you happen to have an oscilloscope and AC signal injector handy let me know....

2. Start by measuring the resistance of the entire 25 and 6 volt circuits (separately) at the point where the secondary was connected (complete circuit continuity test). If it's Infinite, you've got an open circuit. Then follow the circuit backwards one component at a time testing resistance from that component and the end of the secondary at the other end of the circuit. Keep going until you suddenly get a finite resistance value on your OhmMeter. Then you know it was the previous component or associated wiring which was open.

2b) Alternatively, start at the same end of the secondary and work forwards, measuring each components resistance from itself to the secondary and stop when it goes from finite to infinite.

Replace the wiring/component found to cause the break-in-circuit and do a complete circuit continuity test. If still open continue.
 
You're right it's current not voltage that kills. 65 milliamps can kill you. But it's the pressure (voltage) and resistance (MegaOhms for skin) that determines the current. I=V/R.


Since your pinball machine was never expected to go into space or operate far from help, there will be no backup power supply (that's what repair technicians are for!).

Your next step is to figure out where your open (break in the) circuit is for each non-operating circuit - power off.

This will be way easier if the transformer secondary's are disconnected.

Now it is complicated a bit by the fact that it is a completely AC circuit. Capacitors can be happily in-series and act effectively like a time-delayed wire (delay dictated by capacitance and in-series resistor). If there is a capacitor in-series with the circuit that will blow the DC resistance measuring technique (2) below out of the water completely.... You'll get a (very) brief reading and then an open circuit. I've never used it but you can do an AC circuit continuity test with a 1.5V battery in series with an 8 Ohm speaker. Use this to test as in (2). If you hear a 'click' throught the speaker then you have a closed circuit.

Use sleepy's method of checking caps by eye. I'd replace all electrolytics anyway (they age badly but they're cheap).

1. If there are caps in series with the main circuit you're going to have to check the continuity of each (non-capacitor) component and wiring separately or use the battery/speaker technique above. If you happen to have an oscilloscope and AC signal injector handy let me know....

2. Start by measuring the resistance of the entire 25 and 6 volt circuits (separately) at the point where the secondary was connected (complete circuit continuity test). If it's Infinite, you've got an open circuit. Then follow the circuit backwards one component at a time testing resistance from that component and the end of the secondary at the other end of the circuit. Keep going until you suddenly get a finite resistance value on your OhmMeter. Then you know it was the previous component or associated wiring which was open.

2b) Alternatively, start at the same end of the secondary and work forwards, measuring each components resistance from itself to the secondary and stop when it goes from finite to infinite.

Replace the wiring/component found to cause the break-in-circuit and do a complete circuit continuity test. If still open continue.

You just blew my mind man, I have no idea what most of that means, lol. Ill print that out though, maybe show it to this guy thats coming over. He owes my dad a favor and I guess he(my dad) thinks the guy can fix it or something.
 
OK, hopefully your dad's mate can sort it out.

Couldn't find any Gottlieb, but I had a look at a couple of Williams 1972 schematics and it all looks pretty straightforward.

There's virtually no silicon at all and hardly any capacitors either. Interestingly (to me anyway) there _is_ a bit of DC for the jet bumpers, so there are 4 diodes forming a bridge rectifier (big diamond on the right) with a big filter capacitor across the DC output. There is also another 10A fuse in series with the DC output, but everything else would work even if that fuse was blown.

One question - have you checked the 'tilt' switch and connected relay? I just noticed on the Williams tables that if that switch closes, it activates a relay which open circuits almost everything on the 24V circuit and everything on the 6V playfield lights circuit, but leaves the backlights on so you can see the tilt light. The relay closes a make/break switch. If either tilt or that make/break switch are broken or stuck.....
 
If there is a capacitor in-series with the circuit that will blow the DC resistance measuring technique (2) below out of the water completely....
You could short a series coupled (mounted) capacitor to check circuit continuity (no breaks in the circuit) but this will not check the capacitor. This is only when using the DC resistance measuring technique. Note that you do not short a parallel coupled capacitor to check for circuit continuity. This is a capacitor connected from lead to ground, for instance, across an input or output stage of a circuit. Leave parallel coupled capacitors alone and go ahead and check the circuit.
 
OK, hopefully your dad's mate can sort it out.

Couldn't find any Gottlieb, but I had a look at a couple of Williams 1972 schematics and it all looks pretty straightforward.

There's virtually no silicon at all and hardly any capacitors either. Interestingly (to me anyway) there _is_ a bit of DC for the jet bumpers, so there are 4 diodes forming a bridge rectifier (big diamond on the right) with a big filter capacitor across the DC output. There is also another 10A fuse in series with the DC output, but everything else would work even if that fuse was blown.

One question - have you checked the 'tilt' switch and connected relay? I just noticed on the Williams tables that if that switch closes, it activates a relay which open circuits almost everything on the 24V circuit and everything on the 6V playfield lights circuit, but leaves the backlights on so you can see the tilt light. The relay closes a make/break switch. If either tilt or that make/break switch are broken or stuck.....

Well its interesting you mention the tilt switch. Before it stopped working, when you'd plug it in the tilt light would be on, now it doesn't. Looking at the schematic thats apart of the start up process, so im thinking maybe something has to do with it. I don't know where the switch is though, theres a thing that has a pinball in it with a switch, some kinda anti cheat. Then theres a pendulum thing. Ill just wait and see what that guy says.
 
the thing with the pinball in it is a tilt switch. If you pick up the front end of the pin the ball will roll down the track hitting the end and completing the circuit. the pendulum thing is another more sensitive tilt switch, where any side to side or front to back shaking will set it off.
And a capacitor is the thing that looks like a barrel with two silver wires, one on each end coming out of it going into the board, they should have silver ends, but not always. if they look like they are bulging at either end, they are bad!
 
Well the machine works....I don't know what happened, I jacked with the spinning metal thing that has tons of switches near it. Then that play field lights came on and the ball got shot into the trough. First ball did nothing, it was like a dead field. Then it got shot back in for ball 2 then everything started working. I don't understand. Only thing I can figure is that the thing that spins and hits switches to start the game got stuck. Today I had the machine on and jacked with it and it spun(a nudge then it went by it self)...and the game started. I really don't know what to do(other then play :) ), at least it seems to work fine.
 
Last edited:
Jeez!!!!

Stuck switch fooled us all.

Can you do one thing for me: take a photo of your schematic and attach the jpg at full res? I'm burning with curiosity now. I want to know if it was part of the coin unit/anti-cheat mechanism, tilt, start-up or end-of-game circuit which was stuck.... As you say - sounds like start-up...
 
Last edited:
Jeez!!!!

Stuck switch fooled us all.

Can you do one thing for me: take a photo of your schematic and attach the jpg at full res? I'm burning with curiosity now. I want to know if it was part of the coin unit/anti-cheat mechanism, tilt, start-up or end-of-game circuit which was stuck.... As you say - sounds like start-up...
Yeah, I really don't know man, my dads making photo copy's of the schematic. That and theres 2 schematics that came with it. One is like declaration of independence style(old and falling apart). The other is newer, so Ill take a full res shot of the better one and post it for ya man. The thing thats weird is, its like the motor that turns it stuck. Ill take a pic of it so maybe you can put a technical name to it, lol. Also the left flipper stuck earlier while I was playing, it was weird, I manually moved it, it didnt feel hung up or anything. It works again though. So should I just get a new soilnoid for that or? Plus whats the avg pricing on those buggers? Also if I buy one, should I buy another for the right flipper?
 
Sounds like the spinning thing's motor is gummed up and needs a cleaning to remove smoke, grease, etc.

Is it greasy or heavy with old grease like a tar or varnish, like it came from a fried chicken shack/burger stand/smoky bar or what you find on the wall behind the stove where you might do a lot of deep frying? Is there a patina of old baked-on grease? Does the mechanism spin freely between the fingers or does it feel slow like it's full of caked-on grease, like an old room fan motor that quits spinning from fuzzy brown gunk?

If so, time to clean it.
 
Forum activity
Help Users
You can interact with the ChatGPT Bot in any Chat Room and there is a dedicated room. The command is /ai followed by a space and then your ? or inquiry.
ie: /ai What is a EM Pinball Machine?
  • No one is chatting at the moment.
      Chat Bot Mibs Chat Bot Mibs: simon.bethke is our newest member. Welcome!
      Back
      Top