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

[teamhex]

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

 

[sleepy]

Check your AC wall socket and cable to see if it still has power. Plug something else in to it.
You might have tripped the circuit breaker by toggling it.
I'd make sure to use a power strip with overload protection, the simple $5 kind that you should be using on a computer system to prevent damage from power spikes.

I also wouldn't toggle the switch on an older machine. They use high power and older circuits may be unstable causing damage.

 

[teamhex]

Check your AC wall socket and cable to see if it still has power. Plug something else in to it.
You might have tripped the circuit breaker by toggling it.
I'd make sure to use a power strip with overload protection, the simple $5 kind that you should be using on a computer system to prevent damage from power spikes.

I also wouldn't toggle the switch on an older machine. They use high power and older circuits may be unstable causing damage.

Checked that, didn't trip the breaker or anything. I was mentioning to my dad that we should use a surge strip. How do I go about checking for damage? I don't really know what to look for. My dads volt meter was reading 30volts across the power switch(when its clicked on) so im assuming the transformer is working. I think he toggled it to fast or something.

 

[faralos]

well find an instruction booklet, check IPDB site for one. check the power on the power supply. look for broken wires, or possibly it's just the power switch. look for fuses inside on the bottom of the cabinet or in the head (that back piece)

 

[Meecro Hyperion]

My dads volt meter was reading 30volts across the power switch(when its clicked on) so im assuming the transformer is working. I think he toggled it to fast or something.

Hopefully you have only blown an internal fuse - check this first.

Secondly, do you know if that's the correct load voltage on the secondary for that transformer? The rapid power-cycling could have forced an arc through the transformer primary(input) winding insulation (which would have deteriorated over almost 4 decades). This would show up as a lower than expected voltage at the secondary(output).

Check power supply recification next - Diodes, power resistors and filter capacitors in that order.

The hum and weakness in your flippers (when it was working) is probably a bad solenoid actuator, or maybe (but less likely) oxidisation or corrosion of the flipper switches themselves.

Most catastrophic failures in electronic equipment (old and new) are power-supply related.

Get the manual, as faralos suggested, and follow the circuit with your VM.

In-circuit testing is a pain, though, because each component is connected, and you don't get the same values as with testing the component outside the circuit.....

 

[teamhex]

Well im pretty sure the fuses aren't blown. They seem fine. Still what could go out from toggling the power switch? I have the schematic for the table, but is that going to show the correct voltage that's supposed to go across each wire? Its weird, the flippers seemed to be moving at a decent speed, but when the weight of the ball is on it it seems weak. Ill take a look at it today and see what I cant do.

 

[hogger42]

You might try this page. It has some EM repain info on it.

http://www.marvin3m.com/fix.htm

 

[teamhex]

You might try this page. It has some EM repain info on it.

http://www.marvin3m.com/fix.htm

Iv been reading that. I have no idea what to really looks for though.

 

[m4paws]

Sounds like this may be a good place to start, which is just a section of the site that hogger42 pointed out:

When Thing Still Don't Work

Good luck getting it going, that was one of my favorite games as a kid.

 

[teamhex]

Well, I figured it out, some goon put a 3.5 amp fuse where a 5 amp slow blow is supposed to be. It was hidden in the back of the table. Replaced it with the right one....working great :). I still have a weak left flipper and the lights dim a bit when I use the flippers, is that normal? They also still buzz. Thanks for the schematic tip, lol. I wouldn't have known there was a fuse between the cord and transformer.

 

[sleepy]

In-circuit testing is a pain, though, because each component is connected, and you don't get the same values as with testing the component outside the circuit.....

That is definitely right. The mix of connected series and parallel circuits combined complicate the reading of voltage drops, current, and resistances from any specific component.
It's been a Long time since I followed electronics, but when you are attempting to read Ohm's values from any point in a complex circuit, there is the Thevenin Theorem which is an algebraic approach to isolating the correct values. Here's a page on the matter.

http://campus.murraystate.edu/tsm/tsm118/Ch4/Ch4_8/Ch4_8.htm

Doesn't make it fun though!

 

[teamhex]

Well, it was the fuse, I played like 20 games, then I noticed the ball went over a metal thing in a lane coming down. It didn't score, flippers still worked though. Then they stopped working and the lights on the table top went off. I turned it off, and plugged it back in, tried to start a game, the ball loaded, then I used the plunger and noticed nothing was working(like a tilt). So I have no idea, now I cant even start a game by hitting the coin thing. The back lights on, but nothing else. Im assuming this is another fuse issue, but I cant tell by looking so tomorrow im going to test all the fuses and see what I go. Odd, I mean the game worked great, everything scored and did great, then it just stopped working, mid game. I can see this wont be easy. Also the left flipper is quiet now, theres almost no buzz coming from it now, its still slightly weak, but doesnt buzz that loud.

 

[shogun01]

Well, it was the fuse, I played like 20 games, then I noticed the ball went over a metal thing in a lane coming down. It didn't score, flippers still worked though. Then they stopped working and the lights on the table top went off. **snip**

Make sure you check out the link that m4paws supplied. I think that link is very useful. I don't own any pinball machines, but I was able to follow the guide pretty easily and it goes through any possible problem imaginable.

 

[teamhex]

Make sure you check out the link that m4paws supplied. I think that link is very useful. I don't own any pinball machines, but I was able to follow the guide pretty easily and it goes through any possible problem imaginable.

Will do, im sure the fuses are just old, because you can almost see corrosion on the inside of it. I hope if I replace them it will be ok.

 

[faralos]

check your wiring! that sounds like a short or a bad wire somewhere! yeah, I know that's a pain to check all those wires, but you gotta do that anyhow. if they are the old cloth-wrapped kind you'd be better off replacing them anyways. the flippers may just need new solenoids they buzz and you lose power right? worn or bad solenoids usually do that.

 

[teamhex]

check your wiring! that sounds like a short or a bad wire somewhere! yeah, I know that's a pain to check all those wires, but you gotta do that anyhow. if they are the old cloth-wrapped kind you'd be better off replacing them anyways. the flippers may just need new solenoids they buzz and you lose power right? worn or bad solenoids usually do that.

Man im bummed out now...its not a fuse I checked all 4 and they all beep with the meter. Well I guess ill have to check all the wires. How will I know if there's a short, the game played fine for 25 games or so. It just randomly stopped working, and in stages. All the targets stopped working, then the flippers, lights, then the game wont start when I push the coin button. It does have the cloth wrapped wires, its pretty old.

 

[Meecro Hyperion]

You haven't bought a pinball machine - you've bought yourself an adventure!
What's that smell? I think it's the sulfurous odour of a career being launched!
Good Luck teamhex

 

[teamhex]

You haven't bought a pinball machine - you've bought yourself an adventure!
What's that smell? I think it's the sulfurous odour of a career being launched!
Good Luck teamhex

Lol I know how to fix computers and networks not pinball machines. I guess its just going to be a learning process. So no one else has experience with these things?

 

[Phoenixx]

I still have a weak left flipper and the lights dim a bit when I use the flippers, is that normal? They also still buzz.

Thats all absolutely normal for a machine like this, just think about what technology was like when this machine was made. Nowhere near as sophisticated as what we have today, every circuit in these machines is discrete, and the parts in these circuits of course deteriorate over time.

Hence unstable power supplies are probably more the norm than an exception with EEs. The flipper coils, if still the original set, are probably totally through by now. The humming noise they make is to be expected, as a matter of fact some pinsimulations even simulate this humming to make the table feel more authentic.

There are things that can be done though. The power supply regains some stability by replacing crucial parts like capacitors with new ones. (After 50 years its a wonder they still work as good as they do!) Flipper coils and other solenoids can be replaced too, which makes them much stronger again. And if you really want some fresh-flipper-feeling, refresh/rebuild the entire assembly. Everythings possible, in the end only your wallet is the limit,...

 

[Meecro Hyperion]

Why spoil your fun!

Anyway, every hardware problem is different, and requires it's own anlaysis to find the solution. All anyone can do in on online forum is help provide a general direction for you to move in.

My qualification in electronics engineering doesn't help me help you unless I've had exactly the same problem myself with the same piece of hardware or am physically present to carry out the diagnostics and follow-up on the results. Sorry.

In my experience almost every hardware problem I've found a solution for (and that's not as many as I'd like) has been in the power supply, and, although I've never worked on a pinball machine, it is made of components with which I'm familiar.

So by all means continue to post your progress and results of any diagnostic tests you do, and we will help you as much as is possible without actually being there....

The staged failure sounds like a 'die gracefully' failsafe circuit. Once again - power supply. A current detector detector circuit - usually a transistor coupled to a low resistance power resistor - or several in different areas may be tripping (due to faulty wiring or components down-stream) or faulty itself (not as likely).

Replace your bad solenoid on the left flipper - it is draining too much current, thereby dropping the DC voltage at the supply and dimming the lights.

Just a start.

 

[sleepy]

Check power supply recification next - Diodes, power resistors and filter capacitors in that order.

You can check diodes by using the resistance setting on a multimeter.
Set it to Ohms but be damn sure the pinball machine is unplugged and all power in the power supply and circuits has been dissipated to 0 (zero) Volts or you will blow up the battery in the meter. It can explode if power is present in the circuit. You are also risking dangerous shock if you don't. Be sure you know what you're doing.

Connect the meter to both ends of a diode. If it beeps you have current flow with the negative electrode of the meter (as connected to the negative electrode of the battery/batteries in the meter) connected to the cathode lead of the diode and the positive electrode of the meter connected to the anode end of the diode. Reverse the connections. The diode should block the current flow (no beep) with the negative electrode of the meter connected to the anode end of the diode, but if there is a resistor, transistor (emitter-to-collector), etc. bridging the diode, it will draw the current and you will have to disconnect the bridging part to test the diode.

If in any doubt whatsoever, then leave it to a trained technician. Be safe.

 

[Meecro Hyperion]

I still have a weak left flipper and the lights dim a bit when I use the flippers, is that normal? They also still buzz.

Thats all absolutely normal for a machine like this, just think about what technology was like when this machine was made. Nowhere near as sophisticated as what we have today, every circuit in these machines is discrete, and the parts in these circuits of course deteriorate over time.

Phoenixx I bet you 3000 Credits (can't go much higher at present :D) that when that machine rolled off the assembly-line the flippers did not buzz or hum and the lights did not dim when the flippers were engaged. I used to play a six year old '76 EM pinnie and it neither buzzed nor dimmed.

Since the invention of the transistor in 1947 there have only been 3 new components added to the electronic toolkit - all based on it - the diac, triac and SCR.

The technology in that machine is _contemporary_. All we've done since then is minitiurise and integrate.
Even digital circuits are at core made of discrete, analog components.

But you are right in that every component in that thing will have drifted to some extent from it's original value 40 years ago. Resistors by as much as half, caps 1/4-1/2 depending on type, transistor gains down by 1/4. Insulation deteriorates allowing shorts through coil windings of transformers and solenoids.

The noise may be caused by arcing through the coil insulation at some resonant frequency dictated by the inductive reactance of the coil and the resistance or capacitance of surrounding components/wiring,
or a resonant circuit set up between the power supply and the bad coil in a feedback loop jiggling the actuator.

Did you ever hear of the (old) toaster that at a certain stage of it's life began to tune in to a local AM radio station? The inductance of the heating elements and the capacitance of the mains wiring set up a 'tank' circuit which had a resonant frequency which was (by chance) the same as the frequency of the radio station. The loose metal plate at the base of the toaster acted as both the detector diode and speaker.

Everythings possible, in the end only your wallet is the limit,...

That's the bottom line, all right!!! You really need to replace _every_ electronic component in the box, including the wiring.

teamhex you're going to have to replace both flipper coils anyway, so bite the bullet and do them both at once.

But start with the cheap, easy-to-get stuff for the power supply - fuses, diodes, resistors and capacitors. Once it's up to spec you may find that other problems disappear entirely or are reduced in effect.

 

[Phoenixx]

Did you ever hear of the (old) toaster that at a certain stage of it's life began to tune in to a local AM radio station?

Teapots on electrical stoves, but then i think many things would do that if the circumstances are right,...

 

[elton]

and I just thought it was the noises in my head! :D

 

[Phoenixx]

and I just thought it was the noises in my head! :D

I once read a story (i dont know if its actually true or not) about an older lady in some 3rd world country who really believed that her teapot was haunted. Every time the water would heat up she would clearly hear voices coming from the teapot, making her think that some ghosts were trying to contact her. This really drove her nuts as she could not explain to herself what that was. Eventually it turned out that the teapot received some foreign news station, which also explained why she never understood a word of what was being said. Very funny, although i doubt the old lady had agreed. She really believed that she had a bunch of ghosts in da house,...