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Arcade PCB repair - A board with no sound
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- čas přidán 12. 08. 2024
- With this Double Dragon JAMMA pcb we go through troublehooting the sound section step by step. We are discussing theories about audio repair in general and difficulties you might encounter.
This is great stuff. I used your troubleshooting route to repair audio on my Cabal pcb. Thank you very much for this video.
Well done Sir! This is becoming a lost art.
My Chinese Raiden fighters 2 recently lost audio. This is very helpful! Especially considering they're don't appear to be any schematics for the Raiden fighters 2 PCB
AWESOME video. I really enjoy the step by step from beginning to end. You also explain things very well. Please keep doing these!
Thank you very much! I hope you enjoy my newer vids also - some more pcb step by step troubleshooting.
This video is pure gold, thanks for sharing and explaining.
another great video and repair dr. good tip on using a generator to test the amp too and also your diagrams are great. again keep up the great work. a big thumbs up to you sir
Thank you!
As usual very instructive and very well explain. Thank you very much for your videos
Thanks!
amazing troubleshooting, thanks so much
You are bloody good brother. 5☆ Damn straight up you know your stuff. Get ready to come to Australia and work for me mate.
I've got a nightmare one of these with a sound issue. No attract screen music, but plays when game started with missing samples, ie: No sound when hitting opponents. All 3 sound eproms verify ok. Volume works ok.
Thanks, I didn't know there was a freaking volume knob! I'm lucky that's all it was. Then I adjusted the volume on my other games.
Hey man love the videos! Your german accent is fantastic, and thanks for speaking in english! I found your channel by looking for videos on the Atari System 1 boards, as I want a marble madness cab at some point. But! I have a question, what Jamma>Scart board are you using? I have a 15khz PVM that supports RGB and wanted to start maybe getting some broken arcade boards and fix em up. I usually buy broken consoles and fix them, but IBM PC's and Arcade boards are my next logical step. Thanks for the videos! I'm going to be posting them on some repair forums I hang around as your videos are criminally underwatched. Thanks again!
The jamma to scart adapter pcb I'm using I actually made it myself more than 10 years ago. It is useful if you live in Europe because you can hook arcade boards up to an older tv - which usually have a rgb scart input in europe. Nowadays you can buy these online just do a google search for "mak supergun" lots of people make em nowadays.
"criminally underwached" rofl... Thank you for offering to spread the word. :-)
Great video! Thank you for the information. I have two questions for you: What is the brand of the testing pen you are using to test the chips? Do you do board repairs? I have Super Monaco GP (System X) board that works but has no sound. Thank you again
Another great one as usual! I like the detail you go into, explaining not only what you're looking for, but why.
Just a quick question though: What's with all the Double Dragons? Is it a special game for you? Not complaining or anything, just curious as to why you seem to seek those out.
Thanks!
Good question. It is really one of my favorite arcade games. This was actually the last board of a batch of dead boards that I acquired over time. It is actually a nice board to demonstrate some arcade design principles, the pcb quality is really good - durable traces, no lifting pads etc. which allows easy rework and also the schematics are well documented and available on the web. Never the less I am beginning to feel as well that I need to address some more different boards. Next video coming up will probably be about a centipede or maybe a road runner system 1.
I learnt much from it :) Can you make pls a video about Video Signal Generation Cuircuit Repair?
Did you already check out this vid: czcams.com/video/TKOjHXlzkVw/video.html
It covers the basics of the end stage of general video circuitry. Other board repairs I did cover video issues, like the double dragon repairs, combatribes, centipede etc.
What model is your logic probe? I like the light placement vs all the cheap ones of today with the red/green LEDs.
Thank you.
It's an HP (Hewlett Packard) 545A. Maybe you can still get one used on the bay like I did. But basically any probe should work that can differentiate between the three states high, low and "not connected". The "memory" function is a nice extra.
👍❤️
Can I splice the speaker connection(2-wire) from the board to an analog speaker without anything in-between?
I’m trying to swap speakers in the Unico MVSX.
Hi, would you be able to tell me where you get your sockets for the ram chips from? I need to replace a few chips on my galaxian PCB and I figured I'd put in a socket for good measure. Keep up the good work on the channel. I love to learn!
Always really happy to hear when people mention that they find my videos useful. I mostly get the chip sockets off of ebay. Galaxian uses a couple of 18 pin 2114 ram chips I think. Just search ebay for "DIL 18 socket" and you should find plenty. Look for the ones with "double sided" metal contacts (like the ones I used in my indiana jones pcb repair, I am talking a bit about what makes a good ic socket in that vid).
I also have a double dragon pcb with a no music and no coin up sound. Sound effects work but somewhat quiet for being cranked on the audio pot.. got the hum from the upper left portion when I touched it. Can I safely assume it’s the ym2A4A fm chip that needs replacing? I have a logic probe also but very new to pcb repair. Changed a few caps , resistors, transistors in pinball tho. Thanks in advance
Well if the digital effects work then it is at least save to assume that the sound cpu circuit should be fine, an probably there is something wrong with the fm synthesis. But maybe its not the yamaha chip - could also be the "glue" chips around it. You could actually try to check with your logic probe to see what is going on.
What makes that System 1 board unrepairable? Too much physical damage?
Looks like that Double Dragon had some corrosion. It seems to be a common thing with that game. The last one I fixed had a couple corroded vias in the video section. They looked fine visually, but had no continuity.
When I got that system 1 mainboard it already had some custom chips missing and also traces had obviously been ripped off the board when they were removed. It would really be very hard to restore that one. But as I said it serves well as an ic donor.
hello and first of all thanks for your good video. I stumbled on it because I'm trying to fix this other Technos board, a Shadow Force 2 that has this sound issue: plays just indistinguishable noises and as I raise the volume nob it plays a ritmic sound like bup-bup-bup every half second. Touching the amplifier it plays a noise so it seems that it is working. I will try to attach some audio input to it but don't have a wave sound generator so I should find another way...And I'm waiting for the logic probe and ic tester to come. But meanwhile any suggestion would be appreciated. Besides the sound this board has another issue: the images of the characters are the only one missing from the starting screen where you choose the one to play with to the real game where just the background and the words appear. Also here any suggestion would be really appreciated. Anyway again thanks for your great videos
well if you get anything like clicking and hissing out of the speaker chances are your amp is not the problem. checking out what the sound circuit does with the logic probe would be the way to go. that is also true for the graphical issues. the basics of cause are as always a good visual inspection and maybe trying to reseat some socketed chips.
@@christophzett do you know where I could find the schematics for shadow force pcb or even the double dragon or any other technos PCBs?
Hello fron Brazil, thx for the videos is helping a lot on my humble collection.....i got a cps 1 board final fight, its get sond problens too, but some times i fireup the board and get no sound, then turn off and on again i got sound, but some times in the midle of the game the sound goes away and i got nothing or just buzzcome fron the speakes, can you help? Thx a lot
Thank you very much! Because it is a "resetable" error I tend to think that there could be something wrong with the sound cpu or the sound cpus roms or rams or the chips connecting them. It would be interesting to check the sound cpus state with the logic probe after the sound has failed and the game is still running. The sound cpu should be a Z80 somewhere on the pcb.
doktorzett thx a lot, I have some z80 coming, and I will change the chip, and let's see
I have a double dragon pcb that everything works background music when it starts and as soon as game starts or it goes into the demo mode starts humming really bad faintly here noises but no punching mainly background. Any ideas where to look on the sound section that could be causing it? Def had mouse poop and pee on the sound boards area.
well hard to tell but I guess your sound cpu should of course be working when you have music. also the amp section should not be the problem. There is one page of scematics in the double dragon documentation for the digital sounds. as there is two channels of digital audio and neither is working there could be a problem with the cpu starting or setting up those channels for sound output - so maybe some problematic signal lines in that regard could be causing this. If you have actual visible traces of corrosion that of cause can also be a mayor clue to solve this.
Hi dok just revisiting some PCB videos and was hoping you could explain or more so clarify for me the way the sound CPU talks to the MPU. I'm not sure on the interrupt process. I assume the sound CPU takes priority of the databus after the interrupt call in order to process the ROM data; however:
My thinking here is- the sound ROM data is sent to sound CPU which then sends the info to the Yamaha sound synth chip, then the synth chip sends info out to the amp then onto the speakers. is this is correct?, what does the MPU do whilst this is happening is the purpose of the interrupt, to tell the MPU to halt all other activity on the data bus lines?. If that's the case how does the graphics get written to the screen?. If you could sort of clarify the priority table of data activity it would appreciated my friend.
Also on the chip enable signals (more for future clarification) should they always be toggling?- in other words if i come across a ram or rom with a stuck chip enable signal either high or low ( I know the vast majority have an active low enable so not sure if a stuck low CE is a bad thing or not) - does that indicate that the something down the line with the glue logic or the rom/ram ic itself is bad.
Hope this wasn't a mouthful for you mate and any help is really appreciated!, as your detail in these videos are second to none .
Cheers Franky
Hey, thank you very much first of all!
ad 1) Well the Roms don't really send out continuous data, the sound cpu would have to actively transfer the sound data from a rom to the sound chip. The purpose of interrupts generally is to make a cpu aware that an event outside of the cpu occured witch is important for the further processing. so for instance if the main cpu wants the sound cpu to start playing some background game music it could be done in a way that the cpu provides the desired music tune code on the data bus and then interrups the music cpu with than plays the song it sees requested on the bus.
ad 2) chip enable signals may toggle (typically on the game roms and game rams) or may be high all the time (maybe typical for garaphics data eproms or palette roms) but newer low all the time (which would mean they are newer selected). Depends on the circuit architecture.
Hope I could clear some things up!
@@christophzett Very welcome my friend! Thanks for the reply Dok- kinda of makes sense, just a few things with regard to interrupts- so confirming it is the main CPU that interrupts the sound cpu not the other way round? So question does everything goes through the main CPU at all times and it then respectively interrupts whatever device it requires to perform the action?. To digress abit what happens when we have a push button input for example. How does the CPU process that interrupt?. Secondly i assume you mean never(newer) low all the time with regards to AD2 answer, if so - even though the rom/ram(or whatever device) has an active low enable signal it should never be stuck on low just either toggling or high" inactive" at any given point. Thanks again for the help D
did you use a logic probe or logic analyzer? sorry for the noob question
I used a logic probe (the proble with the red flashing light at the tip). This device can of cause just look at one signal at a time. A logic analyzer is a much larger and is able to check 16, 32, 64, 128 or more signals simultaneously.
Are u in USA?
Can u repair
Do you use jamma to scart adapter?
This is tv ? Or monitor?
Yes, I do use a jamma to scart adapter. This is not a tv, it is an arcade monitor type WG K7400. I made a scart cable for the monitor - that's what might make it look a bit confusing. :-)
doktorzett
Thanks
hizz and hum are different
Have you ever worked on a mk1 soundboard?? I've been trying to fix mine and theres not a whole lot as far as a guide on mk1.. its frustrating all the stuff I found is mk2 and mk3 guides
No not yet. I actually do have an mk1 board with sound board but it's working fine. What is the problem with yours?
It doesnt play sound at all .. so I'm just replacing almost all the caps. It says rom u2 and u3 failed test ..
Do you have the means to check the eproms u2 and u3 (read them in an eprom programmer and check them against mame roms)?
No unfortunately I dont . When I turn on the mk1 arcade everything on the main screen that pops up and in the bios it shows everything light up green. But when I check the other options screen and check for volume I wish I could send u an image to show exactly what it shows. It shows u2 and u3 roms failed. Now I've read that just bcuz it says that it might not actually mean there bad. When looking further I know theres away to actually test them which I dont have. I know the caps are bad some of them. I was looking for power source on the soundboard bcuz the 2 lights on the mk board itself only led 1 lights up.
Yes right u2 and u3 failed does not necessarily mean that they are bad - might as well be some components around them - but it probably means that doing only the caps won't be enough. I would suggest you get a cheap eprom programmer and check them out - thats at least what I would do. Also if arcade games are a hobby of yours an eprom programmer will sure come in handy from time to time anyway.