(Topic ID: 208174)
Manchester, MI
I've gotta head out, won't be back for another day or so.
I mean it looks like the noise is coming in on the transformer - it might sound like an odd question but you did move the machine from one site to another when you completed it right?
It would be good to get an oscilloscope measurement from another machine - what else have you got? If you can't work out where, hopefully someone can chime in where to measure on your other machine a similar AC or DC voltage that's unfiltered/unregulated from it's power supply.
Quoted from Quench:I mean it looks like the noise is coming in on the transformer - it might sound like an odd question but you did move the machine from one site to another when you completed it right?
Same location. Or put another way, the machine moved around my house as we completed the work, but right now it's plugged into the same location it was when it worked prior to teardown.
If you mean could the transformer have been damaged, moved, jostled, etc., anything is possible. For a game like this, the transformer is mounted to a back plane along with the rectifier. It's then moved as a single unit in/out of the machine. I assembled it on the bench and tested it on the bench. However, I can't stress enough, I found the whole through-hole soldering of wires to the rectifier awkward at best. Whiskers, shorts, solder blobs... I didn't find any, but anything is possible.
Meanwhile I'll try to find a period-correct transformer/rectifier combo to swap with, and also get my other rectifier board ready for some kind of swap as well.
Quoted from Quench:It would be good to get an oscilloscope measurement from another machine - what else have you got? If you can't work out where, hopefully someone can chime in where to measure on your other machine a similar AC or DC voltage that's unfiltered/unregulated from it's power supply.
I have a TOM, a TOTAN, a BoP, and a BM66. Probably the BoP is the oldest but still 10 years newer than the FS. I'm not sure if that's helpful.
Sounds like we are getting close to pointing at the transformer but its hard to understand how that is possible. Just to eliminate all variables, have you checked the power from the wall outlet?
Quoted from BJM-Maxx:Sounds like we are getting close to pointing at the transformer but its hard to understand how that is possible. Just to eliminate all variables, have you checked the power from the wall outlet?
Unfortunately, I don't think my scope can handle 120V (unless I misunderstand my scope specs, which say 50v peak to peak). If I put some kind of resistor on each lead, I could just plug my scope right into the AC power coming off the circuit and check the waveform for noise, right? Any advice on what level resistor?
Also, I'm more inclined to think it has something to do with the way I attached my transformer to my rectifier...
Quoted from jsa:Also, I'm more inclined to think it has something to do with the way I attached my transformer to my rectifier...
Something is actively generating that noise, your soldering is not at fault.
To me, this noise we're seeing is coming in from your wall socket probably from a bad switch mode power supply or inverter in the house. Do you have solar panels?
Have you still got the original EMI filter from the game? It might have been doing a better job at rejecting the noise. Maybe you could hook it inline with the direct line cord you've got.
Are you friendly with either of your neighbors? Maybe you could run a long extension cord from their house to power the machine and see what happens.
Or what's the chance you have a UPS (uninterruptible power supply) you could hook the machine up to?
.
Quoted from jsa:If I put some kind of resistor on each lead, I could just plug my scope right into the AC power coming off the circuit and check the waveform for noise, right? Any advice on what level resistor?
You'd need to hook up a couple of very high value resistors in series to create a divider circuit. See below:
Of course I need to stress that you exercise extreme caution to prevent shock. The line peak to peak voltage is near 340V.
If you don't have these value resistors tell us what you have that's in the vicinity.
MeasuringLine.jpgHave you got an old fashioned AC power pack you could measure the output with your scope? Something like a 9VAC, 12VAC or 15VAC power pack? If you haven't got an AC unit what about a DC unit? Will save you messing around with hooking resistors to your line cord for measurements.
Quoted from Quench:To me, this noise we're seeing is coming in from your wall socket probably from a bad switch mode power supply or inverter in the house. Do you have solar panels?
HOLY #$%^!
I need to sit down for a second.
I have an elaborate solar panel setup in my house. I'm a beta tester for some newer inverter technology. Unfortunately, as part of the beta test, some equipment failed back in December of 2017. We had a few months of downtime as we re-worked some of the system.
We acquired the Future Spa in January, and began working on the project in February. This is all during the time the solar panels and inverters were offline.
The machine then was torn down and the restoration began.
I've had various ups and downs of the inverter system, which is fairly unique. It's a great system, but I've been helping the company work out the bugs. We brought it back online and fully stable in August and early September.
We then completed the restoration, all after the panels have been fully operational, as well as the batteries and inverter system.
So, bottom line, before the teardown, no inverter. After the restoration, inverter.
Quoted from Quench:Have you still got the original EMI filter from the game? It might have been doing a better job at rejecting the noise. Maybe you could hook it inline with the direct line cord you've got.
I do have that filter, but I suspect we would get the same results. I think we have our smoking gun at this point, don't you? I wonder how I can do a better job filtering the inverter noise from my power system.
Quoted from Quench:Or what's the chance you have a UPS (uninterruptible power supply) you could hook the machine up to?
THAT I can do. I have a UPS for certain systems in the house. Long story. I'll make that happen.
Quoted from Quench:You'd need to hook up a couple of very high value resistors in series to create a divider circuit. See below:
Of course I need to stress that you exercise extreme caution to prevent shock. The line peak to peak voltage is near 340V.
If you don't have these value resistors tell us what you have that's in the vicinity.[quoted image]
I will test with the UPS first. If the problem goes away, I'd rather focus on cleaning my power...Unless you think a better EMI filter would help this game?
Quoted from Quench:Have you got an old fashioned AC power pack you could measure the output with your scope? Something like a 9VAC, 12VAC or 15VAC power pack? If you haven't got an AC unit what about a DC unit? Will save you messing around with hooking resistors to your line cord for measurements.
I do have various AC power packs probably lying around, and DC units. Can you explain a bit more about how I would use this?
I almost edited my wall socket question to ask if you had a dimmer somewhere very partially dimmed. I did not think about solar panels. It sounds like you also have standard grid power. Can you just power down your inverter?
Quoted from BJM-Maxx:I almost edited my wall socket question to ask if you had a dimmer somewhere very partially dimmed. I did not think about solar panels. It sounds like you also have standard grid power. Can you just power down your inverter?
I can power down the inverter, but as I'm part of a beta program, I need to contact the company before I do that (long story, we're monitoring and building data for this machine learning system for power shifting). Meanwhile, I plugged an extension cord into a UPS but I'm still getting noise. I need to figure out if I'm hooked into the UPS correctly, stay tuned.
This seems like such an amazing solution...however somehow I'm still getting noise even through my UPS. This doesn't say much, the UPS is old, and who knows how good a job it's doing of line conditioning when not on battery. I could pull power and have it run on battery... Hmm...
Anyway, this is plugged into the UPS, fuse F1, F2, F3 and F5 removed, line power bypassing the cabinet wiring/EMI filter, and captured across the large ceramic resistor:
Screen Shot 2018-10-25 at 8.47.44 PM (resized).png
Same results with cabinet wiring... I think I'll just pull the plug on my source power. (Yikes)
Ok... well this was a weird experiment.
When grid power was removed from the UPS, and the UPS was running 100% on battery, I then turned the Future Spa on (both directly into the power or also through the cabinet wiring and line filter).
The transformer made a LOUD hum this time. There was something goofy going on.
When I measured the same waveform across the large ceramic resistor, I got these weird waveforms:
Screen Shot 2018-10-25 at 9.14.23 PM (resized).png
Screen Shot 2018-10-25 at 9.15.50 PM (resized).png
Returning to grid power brought me back to that "V" with noise.
Anyone care to explain this to me? Note that I do have other devices also plugged into the same UPS...and I can't turn them off.
Dude.
Load the game up in your truck... take it to a friends house without solar and measure it.
In order for the UPS to work; it needs to be completely offline w/ a real sinusoidal output. Most inexpensive ones do not have that feature.
I could defiantly see the 20khz noise coming from the solar + battery inverter. I'd be concerned about it if it does prove to be the configuration.
Quoted from Zitt:Dude.
Load the game up in your truck... take it to a friends house without solar and measure it.
In order for the UPS to work; it needs to be completely offline w/ a real sinusoidal output. Most inexpensive ones do not have that feature.
I could defiantly see the 20khz noise coming from the solar + battery inverter. I'd be concerned about it if it does prove to be the configuration.
Yeah, that was some weird output when disconnnected from the grid!
Tomorrow I’ll shut down the inverter. I now have the procedure that won’t break anything. If it’s proves to be noise from that, it’s progress!
Quoted from jsa:HOLY #$%^!
I need to sit down for a second.
I have an elaborate solar panel setup in my house.
I didn't see that coming when asking the solar panel question..
Quoted from jsa:The transformer made a LOUD hum this time. There was something goofy going on.
When I measured the same waveform across the large ceramic resistor, I got these weird waveforms:
I'm glad the game was effectively disconnected after the transformer. We might otherwise be looking at some damage.
Most UPS produce 'Modified Sine' wave output. It is a brute force simplistic waveform that most AC devices tolerate. It won't look at all sinusoidal. It it a square wave with small 0V gaps between the positive and negative going square pulses. A spectral analysis would show lots of spikes at various harmonics
Your inverter may do a better job of simulating a sine wave and a 20 kHz frequency seems typical. You may be able to filter that out with something you plug the machine into. More modern switched power supplies would probably not be bothered by that sort of thing.
Quoted from BJM-Maxx:Most UPS produce 'Modified Sine' wave output. It is a brute force simplistic waveform that most AC devices tolerate. It won't look at all sinusoidal. It it a square wave with small 0V gaps between the positive and negative going square pulses. A spectral analysis would show lots of spikes at various harmonics
Your inverter may do a better job of simulating a sine wave and a 20 kHz frequency seems typical. You may be able to filter that out with something you plug the machine into. More modern switched power supplies would probably not be bothered by that sort of thing.
To be clear, the super weird waveform is from my UPS system’s simulated sine wave. My machine and the power of the house never sees that sine wave because it’s power backup only for my telecom gear (and has been tested fine in that gear for many years). I only tried it to see if I could get a clean sine wave without any inverter noise.
My inverter noise (if that is the culprit) is a separate thing, and I’ll try shutting that down today and see if the noise goes away.
Quoted from Atari_Daze:How close is your nearest neighbor, can you run an extension cord just to test?
What about a portable gen set, have one of those?
This thread has become popcorn worthy - well for me at least.
[quoted image]
None of those options are possible. The neighbors are just too far. Shutting down the inverter for a few minutes is easy.
Oh, believe me, this is hysterical to me as well. If this is the cause, essentially 1979 Bally failing to precisely predict the future when people have solar panels and prototype inverters, I’m going to be thrilled.
Quoted from Quench:I'm glad the game was effectively disconnected after the transformer. We might otherwise be looking at some damage.
What’s bugging me is that my UPS also has an AVR (automatic voltage regulator). There shouldn’t be noise passing through that source. The power is converted from AC to DC then back again.
Quoted from jsa:The power is converted from AC to DC then back again.
Right, but with the IGBTs firing... does that not introduce noise by design, hence some of the primary problems with DC power inverters?
Quoted from jsa:What’s bugging me is that my UPS also has an AVR (automatic voltage regulator). There shouldn’t be noise passing through that source. The power is converted from AC to DC then back again.
We might be counting our chickens too early.
If you've got something like a 15VAC transformer power pack, plug it in and hook up your oscilloscope to its 15VAC output and see if there's any of that noise.
Quoted from Quench:We might be counting our chickens too early.
If you've got something like a 15VAC transformer power pack, plug it in and hook up your oscilloscope to its 15VAC output and see if there's any of that noise.
I have transformer packs, I have to see if I have ones that just reduce the voltage. I must somewhere.
Quoted from jsa:Here are a couple shots I took trying to get signal out of a 120W AC to 32W DC transformer pack.
So it's still there. Got a pic of the wave repeating twice? The voltage is going under zero so something isn't right for DC. Can you post a picture of the transformer label?
Quoted from jsa:It's weird.
Your oscilloscope can't scale the image so you're missing the peaks. You might want to invest in some oscilloscope probes so you can X10 the input. They're pretty cheap on ebay. You'll just need to get some BNC connectors to mate them to the oscilloscope or get the official BNC adapter.
Quoted from jsa:This one is 120V AC in and 24V AC out. Here is the wave.
Here is zoomed in:
Yeah the issue looks about the same to me. The switching interference is about 2V peak to peak on that 25VAC output. On your 43VAC output at the pinball transformer is was about 3.5V peak to peak. With the stretched sample in picture 2 it calculates more accurately to around 24.5kHz.
Quoted from Quench:Yeah the issue looks about the same to me. The switching interference is about 2V peak to peak on that 25VAC output. On your 43VAC output at the pinball transformer is was about 3.5V peak to peak. With the stretched sample in picture 2 it calculates more accurately to around 24.5kHz.
I'm going to shut down my inverter next, because...why not. If it shows a clean signal, we'll keep moving on from there. This is fun.
Here is my results with no inverter. This is measured across the large ceramic resistor on the rectifier. F1, F2, F3 and F5 fuses removed.
This is my regular wall outlet power:
Screen Shot 2018-10-26 at 9.19.10 AM (resized).png
Zoom in:
Screen Shot 2018-10-26 at 9.19.40 AM (resized).png
Here is plugged into my UPS line conditioner (not on battery):
Screen Shot 2018-10-26 at 9.12.29 AM (resized).png
What does this tell us?
Quoted from Quench:Feel like reconnecting everything in the game and see what happens?
Yep. Here we go. I have to rebuild that connector but shouldn't take too long.
OMG
This was AWESOME
you two are amazing (jsa & @quench)
Quoted from Quench:Do you have solar panels?
How on earth did you think of this!!!
Laval, QC
Quoted from Atari_Daze:How on earth did you think of this!!!
I was looking up switch mode power supply frequencies earlier and some web sites mentioned inverters in the conversation and well inverters are used with solar panels. To be honest I almost didn't bother asking the solar panel question because I was expecting the answer to be no.
All good.
Before we go any farther with this...
We need to thank some folks here. Tons of you helped out and all deserve thanks for supporting this process. However, I need to single out @quench, who really took an insane amount of time helping me understand all this. Secondly, @barakandl, who not only took the time to really dive deep on some troubleshooting, also CLEARLY makes a rock-solid rectifier board, which has now been proven by countless waveform analysis recordings. Folks like @zitt, @bjm-maxx, @vid1900 and so many others.
I think what this proves (beyond a shadow of a doubt) is that for any service professionals responding to early Bally lamp latching, before spending a ton of time fixing an MPU board or adding resistors, ask them before you truck roll if they have solar panels and an inverter.
What a journey. Wow.
Now I have to figure out how to clean my AC power in my house. Any suggestions? 
Quoted from jsa:Now I have to figure out how to clean my AC power in my house. Any suggestions?
Actually yes, you should request a power quality study be provided by the solar power company. Your results have ramifications they need to consider. Your product that was effected is a pleasure device, what about those on life saving electronic equipment. They should be very interested in providing a product to the market that can filter out such harmonics?
Or just move. 
@Quench, this one is white paper worthy!
Quoted from Quench:Wow, what a most unique problem. Your oscilloscope was invaluable in diagnosing this..
Actually, you were.
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