That hum is the 60Hz netfrequency that is getting into your speakers via an earthloop. The correct sollution was indeed to isolate the earths. I'd say job well done!
The 60Hz hum is definitely present, and that would have been an issue from Factory I should imagine, given the earthing issue. The other "buzzing" however is a noise introduced from the display processing on the LED display board. Some kind of computer / swithcing noise. Unfortunately a side effect of LED Displays. Luckily a good ground can reduce that type of noise also. You can sometimes tear your hair out looking for a ground loop when the earthing was done that one from factory.
Ron's interpretation of the german instructions and the come on people endless loop about the placement of the instructions that followed had me in tears! Big shoutout to you for pumping out these videos!!
If someone wants to fix things different, or film and edit how you fix them different, then let them start their own RUclips channel and do it themselves. Then they will see that just the way you do it drastically increases the amount of time it takes to fix a machine, and they way they are talking about doing it increases that time probably 3 to 4 times that amount. Comon' People. This has been an amazing series Ron, I am loving it.
This serie was very fun to watch. Story about Bubba shot the pinball and the location where you found this machine makes it even better. Great work Ron and Joe!
Great job tracking down that ground loop! Back in the day, my employer sent me to a one week course on proper grounding techniques for multiple "box" or board devices... like a computerized car, plane or spacecraft. Not an hour in that week that was not packed with content. Grounding is not a simple thing!
Only a couple problems. I don't have a Star Trek pinball to test this on. LOL. I don't think i ever will, and I bet the Star Trek is becoming more and more rare as time goes on. Thank you for saving this machine cause with all the work you completed it could have easily been scrapped by some other peoples. Come on peoples.
Hum = 60 hz noise, Buzz = 120 hz noise. 120 hz will be after full wave rectification, and the power filter caps are supposed to smooth out that ripple. If you have power supply noise on your grounds then it can find its way into the audio circuit. I’ve learned this from building/modifying various audio circuits/guitar amps. Sometimes star grounding can get rid of it or greatly reduce it. Other thing that can happen is the noise can be coupled to ground wires running parallel for long distance with other noisy wiring. Also sometimes too many ground connections can create a ground loop, which you generally want to avoid in audio circuits, especially in any kind of high impedance circuits.
I've been annoyed with the high score, game score buzz on my Bally Supersonic since I bought it in '96. I just put Scotch tape on the screw pads that connect to the backbox ground. The annoying sound is gone! This goes against everything I've read about connecting the grounds together on these machines, yet it works! Thanks Ron
I am impressed with how well you can work on devices and hold a cemera and describe the work in detail, often at length wihtout a break. My ADD brain would completely wreck that. Once agian a great repair series.
Excellent!! Coming thick and fast! Definitely German. Pin is big in Germany! My Banzai is in Deutschmarks and my Road Kings defaults to German language on boot up.
Haha so good. My Kiss was making a racket and I couldn't get to it fast enough to add some nylon washers, and it worked like a champ! Thanks so much Ron :) Oh yeah. Hankin is/was an Australian company that made 5 pinball machines back in the early 80s. The most popular being The Empire Strikes Back with infinity backglass, and a playfield design that is a cross between Space Invaders and Firepower. They only made 300 and there is quite a few in the USA because of the Star Wars theme.
Wow! A lot of good information for me on this video. Thank you Ron! And pinball instruction cards, labels, score cards ... incredible site! Great video.
What so many people and even engineers forget. Ground is not ground, ground is a wire leading ground. As such ground has an inductance, a capacitance and a resistance property.
Joes German lessons, priceless... Yeah chasing down ground loops is difficult, frustrating and time consuming... But you fixed it and that is what counts, as its often the case in electronic servicing that you don't always understand what the reason for the fault, but you fix it anyway and move on....
Yeah I mentioned that on a Data East we had in, I said in the video I wasn't even going to try because hardly anything works! There are about 20 things to try though, they work on some games. thank you for watching Thorn Mountain!
Ye olde ground loop! I helped some kid the other day with his car audio with the hum and alternator whine. It was a whole hold my beer moment with a screwdriver and a small piece of wire. Kills all the noise instantly. Fun times!
I can tell you’ve played a few of these machines by how many saves you get when testing. Also, it took a few listens to hear they are trying to play the Star Trek theme music.
It's coming out very nice indeed. I seen the video of the other trek game you put up 4 years ago, that one seemed to have more snappy flippers is that something adjustable in these. Looks fun to play.
Pac-Man has a couple things that cause that, one is dirty fuse holders in the bottom, but usually those will make a black bar scroll through the screen too. The capacitors in the sound section of the pcb will fix any remaining hum, usually.
Great job. It reminds me of back in the 80’s when we would put aftermarket stereos in our cars and trucks and get that annoying engine whine. Had to isolate the ground.
@@scottgm321 yes but somehow the ignition noise was being picked up. When you hear interference in a car that goes with the RPM of the engine it's the ignition system that's making the signal. A car ignition system is basically a spark gap radio. We suppress the transmission by running suppression spark plug wires. If you've ever torn a spark plug wire apart there's no wire in it. There's a carbon ribbon. You can get copper spark plug wires. But they're an oddity. I've run solid plug wires. Talk about interference. Forget about having a sound system in your car then. People next to you will hear your engine in their sound.
It seems like you were able to solve some of the issues by providing a more steady ground, but the biggest issue is that the grounding plane being used is "dirty", so isolating the sound board from that ground isolated it from the issue. I'm guessing on some machines the ground introduces the hum so isolating works on those machines, and on others the hum is in the circuitry so caps/better grounding fixes those scenarios. Good to have a few different tools in the tool box for fixing these issues.
Yeah I agree ultimately the problem is the ground is dirty, but there seems to be no way to fix that if it's happening. Hard to find a 1 shot kills all scenario unfortunately!
@@LyonsArcade tried everything with my '80 Space Invaders, it continues to have a nosiefloor hum and a processor buzz in time with the (LED) displays, although it is nowhere near as bad as it was when i first got it. Looks like the BALLY BUZZ is a thing!
Hankin was an Australian pinball maker … FJ is a famous Australian Holden car, early fifties. Hankin also made Dennis Lillie pinball, about the great test fast bowler (cricket). … Really nailed the hum Ronnie. silence is golden!
I remember Dennis Lillee and our Sir Richard Hadlee in their hey day..that's when cricket was worth watching now its this powerplay shit..don't understand it
How did they make it so that it plays (little bites of) the Star Trek TV theme when you start and end the game, but when you power on the machine it plays freakin' Home on the Range?? Somebody at Bally, as the Brits would say, was seriously taking the piss.
Joe, if they don't like how you do your videos, George Carlin has one thing to say about that..... ....George Carlin fans will know! Keep on keeping on, buddy!
Like your videos. You didn't try removing the grounds that you connected together on the regulator board. One of the reason that you would run separate grounds out, is to prevent hum on the audio. Ground loops are hard to find.
Hummm... you may be onto something :) It might be the high voltage capacitor ground but those LED displays don't use the high voltage. I'll mess around with that next time I do one...
JOES CLASSIC, Ground loops means multiple wires/paths going to multiple "different grounds", meaning Not all ground wires tied to ONE Star Ground. I'm not sure why LED Displays would magnify the 60hz hum or the sound amplifier is amplifying the Display hum noise. What I'm saying is the actual Displays are generating a noise hum that the sound amplifier is amplifying. Your DVM meter has an AC Frequency mode to measure the frequency so is it 60hz when measuring the frequency on the ground screws? You take your DVM meter and connect the Black probe to the Earth Lug located on the AC outlet ( not the neutral socket ) and then connect RED probe to the screw on the sound board, what frequency does it measure? and also measure the frequency on the grounding pin on the displays. After you have got the frequency when use the milliohm mode on your DVM meter and measure from earth (referenced )to each of the ground pins and ground screws. The milliohms reading should all be the same measurement. You take all your ground pins/wires and connect them to only ONE Star ground. Using Nylon Washers is putting a band Aid because it won't work for all different types of pinball games. What you're doing is "floating the ground" on the sound board when using nylon washers.
- might be a silly suggestion. Have you tried putting a ferite ring on the wires that go to the connector (as near to connector as possible)? It should act as a high pass filter and cut out the interference (hum) Excellent Video as usual - always follow with interest
I just realized a couple days ago the exact same issue Ghillie! I was trying to find cards for a Williams Serenade, similar vintage to your 21, and you're right, they don't have many of the earlier Williams cards. I had to type up my own, I guess we need somebody to go through and submit a bunch of Williams stuff for his site! What I did was find another Williams one that had a simliar layout and changed the text in the file based on pictures of the card I could barely read online. Thank you for watching as always!
32:15 you were cut into another scene before you got completely carried away. LOL Strange that the display ground ties to the audio board of all places.
29:02 Jup it's German. i#M from Germany, but even for me the words "Kugelauslaufbahnen" und "Kugeldurchlaufbahnen" were new to me. Freely translated "Ball out run lanes" and "Ball through run lanes", so it is probably ouitlane and inlane. But I never heard those words before. At this time we also say "oultalne" and "inlane" in Germany when talking about pinball in german. We also say "flipper" and "bumper" and "slinghot". We also say "is lit" and "extra ball". When I think about it most pinball talk in germany uses the neglish terms nowadays. But we use German in the rest of the sentence. For example "Die Kugel ist mir in die outlan gegangen" oder "Mit dem linken Flipper hab ich den Ball nicht mehr gekriegt" oder "In die Bumper und dann direkt raus durch die Oultane"... strange...
You are conversant in English too so you know that a lot of English words are German in nature in the first place so I guess since Pinball as we know it came from Chicago the German pronunciation is the English one.
Ahh the groundloop issue, it's pretty much always the reason for the speaker humming. Because the speaker is grounded in order to work, all the other things inside will find the shortest distance to earth, which can very much be the speaker. See it all the time in the professional audio space when I was working as a mobile cinema operator, plug the laptop into the sound system, no problems, plug the laptops charger in, instant issues, because the laptop charger has no ground of its own, it goes out the 3.5mm audio cable to the ground provided by the sound system itself. I have a soundbar for my PC, the PC is plugged into it via 3.5mm, but the soundbar also needs power (If you want it to run longer than a few hours), and that power is provided via USB, but I couldn't plug the USB into the computer because there would be the annoying 50Hz hum (50Hz here in Australia, 60 in the US), so I had to plug the USB into a powerbrick.
The processing on the LED's and power supply used for on the LED boards introduces quite a lot of noise into the system, which can introduce noise on the 5V line. It's unfortunately going to be a thing moving forward if we want to keep saving these machines. Luckily it can be reduced with the grounding modifications. I was thinking during it that I would probably replace the big yellow cap as minimum as a maintenance thing to reduce issues in the future. I honestly didn't expect it to make a huge difference to the hum. Ground Loops can be so tricky to find sometimes. You can tear your hair out chasing the hum. If the hum is 60Hz, then look for a ground loop. If the hum is 120Hz, look for ripple / faulty caps).
Without knowing or googling it, it would seem to me that the price card would go on the right because most (not trying to discriminate) (c'mon) people are right handed. Where do you keep your quarters? The right front pocket.
I was just playing around but it's pretty obvious if you look at the older ones, people can do it however they want though. Thanks for watching Telletran!
I wonder if the reason that it works on some and not others is the plated through holes ? some installations the screw touches the plating in the hole and grounds it and in some the screw dosent touch and it works ?....cheers
The "Hum" issue is or was multiple issues. You did well to locate a solve for recurculating current (ground loop) . The remaining hum, however, is clearly at 120 Hz - not 60 Hz, and is not a ground loop issue. 120 Hz hum has few sources. Power supply filter capactiros is the only common answer. Reolace the power supply filter electrolytics. If an osciliscope is handy, set scope to AC coupling. Measure the power supply outout. I'm pretty sure you'll see 120 Hz is present at the supply output. My major point is not all Hum is 60 Hz hum. 120 Hz hum is generated at the full wave recifier bridge(s). Large electrolytic capacitors are used to filter the resulting DC voltage. Electrolytics that are no longer able to to meet spec is the overwhelming common reason for 120 Hz in pinball machines, and any other audio systems.
OMG you have never seen a Hankin ! Worked on a mates Empire Strikes Back, tricky suckers as there a hybrid machine half is a Williams firepower and half is a Gotlieb.Duel transformers,was a guy making them in Brisbane Australia in the 80s.Made a few Howzat FJ and Empire Strikes Back.FJ is based on a Aussie car or a GM in your neck of the woods,A FJ utility.
Looking at Bally flyers from the era, it seems that the instructions and points cards could be put on either side. I put the instructions on the right because that’s the way most operators had them in my area. To each, his own.
Its called "ground loops'. This is why there are multiple grounds. Audio logic solenoid. Generally kept separate until last minute when they are " stared together". Main thing is the ground current for one thing doesn't end up being the signal to another thing....
The ground symbol you stated as chassis ground is 'not' a chassis ground, it is an earth ground. My guess is when you grounded it to the chassis you introduced chassis noise, back feeding it in to the sound board. Just sayin. Recapping is really just to get out old possibly soon to fail caps. You can ESR test them. But if you are going to sell the machine, and it is an older one with mostly OEM caps, just recap the whole thing.
Noisey little sound card. Should replace CR3 the blocking diode. If that diode leaks the Z input of mpu stops working. C17 charges to 62volts dc the regulator outputs 12 volts so it wastes 50 volts. Should be 50 ohm resistor in series with CR3 and C17 to save big current rush on start up. Signal to Noise ratio can be altered by a 60 ohm resistor in series with the speaker. Turn the volume up and if the buzz was a constant it will be low and signal higher. One last tjing is run a timer triggered by the "Game over " light circuit. Game over light turns off a relay turns on the speaker and when it turns on a timer will reset the relay giving it 30 seconds or so before shutting off speaker
That hum is the 60Hz netfrequency that is getting into your speakers via an earthloop.
The correct sollution was indeed to isolate the earths. I'd say job well done!
The 60Hz hum is definitely present, and that would have been an issue from Factory I should imagine, given the earthing issue.
The other "buzzing" however is a noise introduced from the display processing on the LED display board. Some kind of computer / swithcing noise. Unfortunately a side effect of LED Displays. Luckily a good ground can reduce that type of noise also.
You can sometimes tear your hair out looking for a ground loop when the earthing was done that one from factory.
Easiest way to stop speakers from humming is to teach them the words.
Thank you, I'll be here all week, Be sure to tip your waitress!
Kate, i'm going to have to admonish you for that joke. Kate..... you're Admonished.
You will have to buy a sink off Donnie now haha oh and I'm still waiting on my coffee I ordered 2 hours ago 😅..can't complain about the service 😅
Ron's interpretation of the german instructions and the come on people endless loop about the placement of the instructions that followed had me in tears! Big shoutout to you for pumping out these videos!!
If someone wants to fix things different, or film and edit how you fix them different, then let them start their own RUclips channel and do it themselves. Then they will see that just the way you do it drastically increases the amount of time it takes to fix a machine, and they way they are talking about doing it increases that time probably 3 to 4 times that amount. Comon' People. This has been an amazing series Ron, I am loving it.
Thank you Brant we appreciate it man, hope you've been well!
This serie was very fun to watch. Story about Bubba shot the pinball and the location where you found this machine makes it even better. Great work Ron and Joe!
Thank you Scoosie, we appreciate you hanging out with us awhile!
I have never seen sling shots that powerful! Holy cow!
Originally that was what you played them with, they didn't have flippers!
That was nice how you stepped thru the options until the hum was gone.
Great work! This is a beautiful machine.
Thank you Vincediesil, we appreciate you watching!
Hi Ron, this has been terrific watching you guys bring this machine back to its former glory. Thanks for such a detailed "series" lol.
Love this pinball! So much fun to play
Great job tracking down that ground loop! Back in the day, my employer sent me to a one week course on proper grounding techniques for multiple "box" or board devices... like a computerized car, plane or spacecraft. Not an hour in that week that was not packed with content. Grounding is not a simple thing!
I used to install car audio and such. Ground loops are a pain in the ass. Great job!
Don't apologize Ronnie..film YOUR videos and edit them the way YOU want..f the critics
You tell em , Naytch!
Only a couple problems. I don't have a Star Trek pinball to test this on. LOL. I don't think i ever will, and I bet the Star Trek is becoming more and more rare as time goes on. Thank you for saving this machine cause with all the work you completed it could have easily been scrapped by some other peoples. Come on peoples.
Great job fixing the hum!
Great explanation of your through process and how to attack a problem like this. Thanks for sharing!
Nice work Ron!!
Thank you Patrick, glad you enjoyed it!
Ron, I just bought a needed logic probe, the one on your parts page. Yes I bought it through your site. Cheers!!
Thanks Patrick, Hope you fix some cool stuff with it!
Sounded just like my Dolly Parton. Have to try the nylon washer trick. Great video. Thanks!
It will probably work, I think it's the same soundboard.
wow that thing is coming along rather nicely! Good Job saving it
This whole thing has been really impressive how you took the machine from what it used to be to what it is now. Really fun to watch! :)
Excellent job!
Thank you for watching Michael!
Hum = 60 hz noise, Buzz = 120 hz noise. 120 hz will be after full wave rectification, and the power filter caps are supposed to smooth out that ripple. If you have power supply noise on your grounds then it can find its way into the audio circuit. I’ve learned this from building/modifying various audio circuits/guitar amps. Sometimes star grounding can get rid of it or greatly reduce it. Other thing that can happen is the noise can be coupled to ground wires running parallel for long distance with other noisy wiring. Also sometimes too many ground connections can create a ground loop, which you generally want to avoid in audio circuits, especially in any kind of high impedance circuits.
Ron --
At this point, don't you think a refit of the REAL Starship Enterprise would have been simpler?
😂
Highly illogical captain 😆
I'M GIVIN HER ALL SHE'S GOT, AVENGERii!!!!
Dammit Jim I'm a doctor not a....pinball repair guy
Its life, Jim, but not as we know it.
I've been annoyed with the high score, game score buzz on my Bally Supersonic since I bought it in '96. I just put Scotch tape on the screw pads that connect to the backbox ground. The annoying sound is gone! This goes against everything I've read about connecting the grounds together on these machines, yet it works! Thanks Ron
I am impressed with how well you can work on devices and hold a cemera and describe the work in detail, often at length wihtout a break. My ADD brain would completely wreck that. Once agian a great repair series.
Thank you fwaynedavis, I appreciate you watching man
Tweak the kickers, I heard kick the tweakers. Thanks Ronnie
Kicking Tweakers is more fun, for sure....
Tweaking knickers?? Wtf 😆
I appreciate how you noodled this out. Great video as always.
Thank you for watching, AppliedCryogenics!
Working great now, you have make a great job. 😎👍
Excellent!! Coming thick and fast! Definitely German. Pin is big in Germany! My Banzai is in Deutschmarks and my Road Kings defaults to German language on boot up.
We're down to the last video! About to put her in Warp Drive!
@@LyonsArcade Note the Stardate Ron!
How strange, what a simple remedy. Love those old sounds the first solid states have. Great video as usual. Great to see it saved from waht it was.
Thank you Simon, separating it from the ground like that isn't really how it should be but at least it sounds good now :) Thanks for watching!
Haha so good. My Kiss was making a racket and I couldn't get to it fast enough to add some nylon washers, and it worked like a champ! Thanks so much Ron :)
Oh yeah. Hankin is/was an Australian company that made 5 pinball machines back in the early 80s. The most popular being The Empire Strikes Back with infinity backglass, and a playfield design that is a cross between Space Invaders and Firepower. They only made 300 and there is quite a few in the USA because of the Star Wars theme.
Wow! A lot of good information for me on this video. Thank you Ron! And pinball instruction cards, labels, score cards ... incredible site! Great video.
Personally, speaking for myself, I love the off the cuff, live presentation style! :D
Greatful you're making these vidoes Ron. Thanks!
What so many people and even engineers forget. Ground is not ground, ground is a wire leading ground. As such ground has an inductance, a capacitance and a resistance property.
Thank you Randy!
what a beautiful game. it looks mint. and plays well. send me a t shirt as a present.
Joes German lessons, priceless...
Yeah chasing down ground loops is difficult, frustrating and time consuming...
But you fixed it and that is what counts, as its often the case in electronic servicing that you don't always understand what the reason for the fault, but you fix it anyway and move on....
Great job!
Great fix, thank you.
Def points for persistence!!
Thanks for sharing. 😉👌🏻
Nice job, now a real challenge, get rid of the speaker hum on a Data East pinball machine. I've never seen many solutions that work on those units.
Yeah I mentioned that on a Data East we had in, I said in the video I wasn't even going to try because hardly anything works! There are about 20 things to try though, they work on some games. thank you for watching Thorn Mountain!
Ye olde ground loop! I helped some kid the other day with his car audio with the hum and alternator whine. It was a whole hold my beer moment with a screwdriver and a small piece of wire. Kills all the noise instantly. Fun times!
FOR SALE : 5 caps, hardly ever used :p
Thanks for your videos, this is so helpful!
Pulled from a machine in use. Untested.
If it annoys you go find a channel that fixes pinball machine and uses screen caps for diagrams!
ME: NO ONE ELSE DOES PINBALL REPAIR LIKE YOU DO!
I can tell you’ve played a few of these machines by how many saves you get when testing. Also, it took a few listens to hear they are trying to play the Star Trek theme music.
Thank you for watching Dan!
It's coming out very nice indeed. I seen the video of the other trek game you put up 4 years ago, that one seemed to have more snappy flippers is that something adjustable in these. Looks fun to play.
My Pac-Man upright has a hum too. I guess I’ll be checking my sound board
Pac-Man has a couple things that cause that, one is dirty fuse holders in the bottom, but usually those will make a black bar scroll through the screen too. The capacitors in the sound section of the pcb will fix any remaining hum, usually.
@@LyonsArcade thanks, you’re the best!
Great job. It reminds me of back in the 80’s when we would put aftermarket stereos in our cars and trucks and get that annoying engine whine. Had to isolate the ground.
Yeah I always had to buy those little blockers. Never made any sense to me though.
Bring back the 80s people!!!!
Engine whine is the input picking up the ignition. That means your input is not shielded well.
@@1pcfred the only input I had in the 80’s were my cassettes. Lol
@@scottgm321 yes but somehow the ignition noise was being picked up. When you hear interference in a car that goes with the RPM of the engine it's the ignition system that's making the signal. A car ignition system is basically a spark gap radio. We suppress the transmission by running suppression spark plug wires. If you've ever torn a spark plug wire apart there's no wire in it. There's a carbon ribbon. You can get copper spark plug wires. But they're an oddity. I've run solid plug wires. Talk about interference. Forget about having a sound system in your car then. People next to you will hear your engine in their sound.
It seems like you were able to solve some of the issues by providing a more steady ground, but the biggest issue is that the grounding plane being used is "dirty", so isolating the sound board from that ground isolated it from the issue. I'm guessing on some machines the ground introduces the hum so isolating works on those machines, and on others the hum is in the circuitry so caps/better grounding fixes those scenarios. Good to have a few different tools in the tool box for fixing these issues.
Yeah I agree ultimately the problem is the ground is dirty, but there seems to be no way to fix that if it's happening. Hard to find a 1 shot kills all scenario unfortunately!
@@LyonsArcade tried everything with my '80 Space Invaders, it continues to have a nosiefloor hum and a processor buzz in time with the (LED) displays, although it is nowhere near as bad as it was when i first got it. Looks like the BALLY BUZZ is a thing!
@@LyonsArcade Maybe that's why it collected a bullet?
Hankin was an Australian pinball maker … FJ is a famous Australian Holden car, early fifties. Hankin also made Dennis Lillie pinball, about the great test fast bowler (cricket). … Really nailed the hum Ronnie. silence is golden!
I remember Dennis Lillee and our Sir Richard Hadlee in their hey day..that's when cricket was worth watching now its this powerplay shit..don't understand it
always seems to be a grounding issue with these things. Great Fix!
Thank you for watching, Dragon Gamer!
It's always a ground on a Chevy too.
How did they make it so that it plays (little bites of) the Star Trek TV theme when you start and end the game, but when you power on the machine it plays freakin' Home on the Range?? Somebody at Bally, as the Brits would say, was seriously taking the piss.
Classic ground loop. 741 is your basic op amp. LM380 is a power amp. Reminds me of my misspent youth doing analog design in the 70's and 80's.
I think this Bubba here might be in danger of also shooting the pinball if he gets too frustrated with it! lol
POW! Thankye very moch
hahahaha no we're gonna leave it alone Chuck U!
I had to do the same thing to my Star Trek sound board. I left the lower left screw out and it was quiet after that. A mystery.
you also need the xylophone chimes with the ArdunoUNO :D
Joe, if they don't like how you do your videos, George Carlin has one thing to say about that.....
....George Carlin fans will know!
Keep on keeping on, buddy!
Like your videos. You didn't try removing the grounds that you connected together on the regulator board. One of the reason that you would run separate grounds out, is to prevent hum on the audio. Ground loops are hard to find.
Hummm... you may be onto something :) It might be the high voltage capacitor ground but those LED displays don't use the high voltage. I'll mess around with that next time I do one...
JOES CLASSIC, Ground loops means multiple wires/paths going to multiple "different grounds", meaning Not all ground wires tied to ONE Star Ground. I'm not sure why LED Displays would magnify the 60hz hum or the sound amplifier is amplifying the Display hum noise. What I'm saying is the actual Displays are generating a noise hum that the sound amplifier is amplifying. Your DVM meter has an AC Frequency mode to measure the frequency so is it 60hz when measuring the frequency on the ground screws? You take your DVM meter and connect the Black probe to the Earth Lug located on the AC outlet ( not the neutral socket ) and then connect RED probe to the screw on the sound board, what frequency does it measure? and also measure the frequency on the grounding pin on the displays. After you have got the frequency when use the milliohm mode on your DVM meter and measure from earth (referenced )to each of the ground pins and ground screws. The milliohms reading should all be the same measurement. You take all your ground pins/wires and connect them to only ONE Star ground. Using Nylon Washers is putting a band Aid because it won't work for all different types of pinball games. What you're doing is "floating the ground" on the sound board when using nylon washers.
- might be a silly suggestion.
Have you tried putting a ferite ring on the wires that go to the connector (as near to connector as possible)? It should act as a high pass filter and cut out the interference (hum)
Excellent Video as usual - always follow with interest
Nice video! Did you put the washers behind the board? Have hum problems with 2 system 11 games, i will try this! Thank you
26:22 Unfortunately that site doesn't seem to have anything for a Williams 21
I just realized a couple days ago the exact same issue Ghillie! I was trying to find cards for a Williams Serenade, similar vintage to your 21, and you're right, they don't have many of the earlier Williams cards. I had to type up my own, I guess we need somebody to go through and submit a bunch of Williams stuff for his site! What I did was find another Williams one that had a simliar layout and changed the text in the file based on pictures of the card I could barely read online. Thank you for watching as always!
32:15 you were cut into another scene before you got completely carried away. LOL
Strange that the display ground ties to the audio board of all places.
Dein Deutsch ist grausam, aber ich liebe Deine Videos, die mir schon viel geholfen haben . Gruesse von einem Deutschen in Neu Seeland.
29:02 Jup it's German. i#M from Germany, but even for me the words "Kugelauslaufbahnen" und "Kugeldurchlaufbahnen" were new to me. Freely translated "Ball out run lanes" and "Ball through run lanes", so it is probably ouitlane and inlane. But I never heard those words before. At this time we also say "oultalne" and "inlane" in Germany when talking about pinball in german. We also say "flipper" and "bumper" and "slinghot". We also say "is lit" and "extra ball". When I think about it most pinball talk in germany uses the neglish terms nowadays. But we use German in the rest of the sentence. For example "Die Kugel ist mir in die outlan gegangen" oder "Mit dem linken Flipper hab ich den Ball nicht mehr gekriegt" oder "In die Bumper und dann direkt raus durch die Oultane"... strange...
You are conversant in English too so you know that a lot of English words are German in nature in the first place so I guess since Pinball as we know it came from Chicago the German pronunciation is the English one.
Ahh the groundloop issue, it's pretty much always the reason for the speaker humming. Because the speaker is grounded in order to work, all the other things inside will find the shortest distance to earth, which can very much be the speaker.
See it all the time in the professional audio space when I was working as a mobile cinema operator, plug the laptop into the sound system, no problems, plug the laptops charger in, instant issues, because the laptop charger has no ground of its own, it goes out the 3.5mm audio cable to the ground provided by the sound system itself.
I have a soundbar for my PC, the PC is plugged into it via 3.5mm, but the soundbar also needs power (If you want it to run longer than a few hours), and that power is provided via USB, but I couldn't plug the USB into the computer because there would be the annoying 50Hz hum (50Hz here in Australia, 60 in the US), so I had to plug the USB into a powerbrick.
29:16 Heute ist ein guter Tag zum Sterben (old Klingon saying... the German version of it... lol)
The processing on the LED's and power supply used for on the LED boards introduces quite a lot of noise into the system, which can introduce noise on the 5V line.
It's unfortunately going to be a thing moving forward if we want to keep saving these machines. Luckily it can be reduced with the grounding modifications.
I was thinking during it that I would probably replace the big yellow cap as minimum as a maintenance thing to reduce issues in the future. I honestly didn't expect it to make a huge difference to the hum. Ground Loops can be so tricky to find sometimes. You can tear your hair out chasing the hum. If the hum is 60Hz, then look for a ground loop. If the hum is 120Hz, look for ripple / faulty caps).
What's the newest pinball machine that you've worked on?
Some of the WPC-95 stuff was about as new as I ever messed with. I like the older stuff better in every way to be honest.
in old tube amps/ss amps with mains hum, check the mains electrolytic cap first port of call!
yes, it's German haha
but ... we must do a litte trainig reading it ;-)
Without knowing or googling it, it would seem to me that the price card would go on the right because most (not trying to discriminate) (c'mon) people are right handed. Where do you keep your quarters? The right front pocket.
I was just playing around but it's pretty obvious if you look at the older ones, people can do it however they want though. Thanks for watching Telletran!
I wonder if the reason that it works on some and not others is the plated through holes ? some installations the screw touches the plating in the hole and grounds it and in some the screw dosent touch and it works ?....cheers
was it humming before the new displays where put in?
Yes, I had it unplugged the entire time we were working on it because of the hum.
ok I just wondered if changing the displays. caused it. great fix
The "Hum" issue is or was multiple issues. You did well to locate a solve for recurculating current (ground loop) . The remaining hum, however, is clearly at 120 Hz - not 60 Hz, and is not a ground loop issue. 120 Hz hum has few sources. Power supply filter capactiros is the only common answer. Reolace the power supply filter electrolytics. If an osciliscope is handy, set scope to AC coupling. Measure the power supply outout. I'm pretty sure you'll see 120 Hz is present at the supply output. My major point is not all Hum is 60 Hz hum. 120 Hz hum is generated at the full wave recifier bridge(s). Large electrolytic capacitors are used to filter the resulting DC voltage. Electrolytics that are no longer able to to meet spec is the overwhelming common reason for 120 Hz in pinball machines, and any other audio systems.
Are those cards printed on acid free card stock?
OMG you have never seen a Hankin ! Worked on a mates Empire Strikes Back, tricky suckers as there a hybrid machine half is a Williams firepower and half is a Gotlieb.Duel transformers,was a guy making them in Brisbane Australia in the 80s.Made a few Howzat FJ and Empire Strikes Back.FJ is based on a Aussie car or a GM in your neck of the woods,A FJ utility.
completely "Foreign" to me, haha I've never heard of a FJ either, thank you for watching justlookin20101!
Come to think of it it it isn't Gotlieb it is Bally
I gotta ask, what's with you and the "Youngbloods?? Tag line. Luv ur content...
It's a good song
@@LyonsArcade no argument there...thanks again for your videos.
Can you tell what tune it's humming?
Just spitballing, add a ground loop isolator to the audio circuit. Belay my idea, nylon washer is the ticket.
Why isn't Captain Kirk in the playfield? Is he on the backglass?
He's front and center on the backglass.
Looking at Bally flyers from the era, it seems that the instructions and points cards could be put on either side. I put the instructions on the right because that’s the way most operators had them in my area. To each, his own.
Would the proximity to the transformer be the cause of the hum ??
It's all in the original spots so I don't know. Maybe!
Awesome job! Sounds like it could use a bit more sustain in the audio.
Its called "ground loops'. This is why there are multiple grounds. Audio logic solenoid. Generally kept separate until last minute when they are " stared together". Main thing is the ground current for one thing doesn't end up being the signal to another thing....
Time to pull out an oscilloscope!
Guten morgen
Round heah we say Good Morning :)
Wird... morishzie bedtar gudden!
Your "Jump to hyperspace" 4 lamp isn't working!
Just Sodder the pins that should fix the hum lol
We're tryin!
der spieler Doppelbonus. Definitely German!
I see it as a grounding wire acting like an antenna from audio circuit or and or the rectifier circuit? I have my eyes closed.
28:42 Yes, it's German
The ground symbol you stated as chassis ground is 'not' a chassis ground, it is an earth ground. My guess is when you grounded it to the chassis you introduced chassis noise, back feeding it in to the sound board. Just sayin. Recapping is really just to get out old possibly soon to fail caps. You can ESR test them. But if you are going to sell the machine, and it is an older one with mostly OEM caps, just recap the whole thing.
You think so?
Noisey little sound card. Should replace CR3 the blocking diode. If that diode leaks the Z input of mpu stops working. C17 charges to 62volts dc the regulator outputs 12 volts so it wastes 50 volts. Should be 50 ohm resistor in series with CR3 and C17 to save big current rush on start up.
Signal to Noise ratio can be altered by a 60 ohm resistor in series with the speaker. Turn the volume up and if the buzz was a constant it will be low and signal higher.
One last tjing is run a timer triggered by the "Game over " light circuit. Game over light turns off a relay turns on the speaker and when it turns on a timer will reset the relay giving it 30 seconds or so before shutting off speaker
yeah it seems like the flippers are just a tad weak
Probably has something to do with current draw in ground circuit._
It's definitely not playing ersatz music, it's playing genuine bits of the original theme.
Mr Minge
He’s an absolute savage
this pinball machine has nintendo sound fx wtf