AES Sound Issues - First time owner seeking help

StompyChar

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Greetings one and all.
I'm a videogame collector on a budget and it's taken me some time to get into Neo-Geo consoles.

Finally some months ago I found someone selling a AES system with some games that I could afford.

However the reason it was affordable became clear to me when I hooked it up at home and found out there were some major sound issues.

There are loud cracks and popping sounds during explosions, voice clips etc.

I figured considering the console had been modified with Unibios, RCA and a fancy LED in the reset button It might have been a little dirty inside and wanted to clean it, but upon opening it up I've found a loose wire coming from the RCA sound that I've not been able to figure out where it should connect, and if that is even the sollution to my sound issue.

So I hope some of you clever gents and lasses could help me figure this one out and turn this first time owner into a further collector and enthousiast neo-geo player.

Thanks in advance.

Neo 1.jpg
Neo 2.jpg
 

ballzdeepx

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Are the sound issues present if you use the headphone jack in the front?
 

StompyChar

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Are the sound issues present if you use the headphone jack in the front?

I never thought about testing this, thank you.
Yes the sound is the same through the headphone jack.

What is interesting is that during the BIOS menu and the initial Neo bootup screen (the tune) it's all fine but as soon as the games start there's the LOUD popping and crackling.
 

Neo Alec

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The short green cable that is loose is for ground. Just connect it to any ground point. Easiest place is probably ground on that composite video jack, same point as that short white cable that'a running to the S-video jack now.

I don't think that's going to fix the issue. You will probably need to remove the board and take a photo of the back area where the audio jack cables are connected.
 

ballzdeepx

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I'd also start by cleaning your cart slots really well, use some cardboard as thick as a game pcb doused in isopropyl alcohol and carefully clean both slots.
If you have something like Deoxit that is even better.

Make sure you clean your game contacts as well.
 

StompyChar

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The short green cable that is loose is for ground. Just connect it to any ground point. Easiest place is probably ground on that composite video jack, same point as that short white cable that'a running to the S-video jack now.

I don't think that's going to fix the issue. You will probably need to remove the board and take a photo of the back area where the audio jack cables are connected.

Neo 4.jpg
Neo 5.jpg
 

Neo Alec

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Well, that all looks good on the back.
 

StompyChar

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I'd also start by cleaning your cart slots really well, use some cardboard as thick as a game pcb doused in isopropyl alcohol and carefully clean both slots.
If you have something like Deoxit that is even better.

Make sure you clean your game contacts as well.

I've ordered some Deoxit (Needed some Compressed air and other bits and bobs anyway) and hopefully that'll arrive tomorrow so I can give your idea a try.

Other then that I do not know what else I can do but reconnect the green wire where you guys suggested it and hopefully together with the cleaning It might magically work again.
 

StompyChar

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So, the Deoxit came in today (Snowfall delay, hoooraaaay...) and I've properly cleaned the slots.
I've also reconnected the loose wire to a ground point.

Unfortunately neither has solved the issue.
 

ballzdeepx

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Just to confirm you are using the front headphone jack correct? Do not use the RCAs on the back for now.
While plugged into the headphone jack- Try to play around with the volume slider to see if it helps in any way, you could also add a small amount to the slider pot as well (assuming you have the top shell taken off)

If this doesn't work I'd consider de-soldering the wires that are tapped off the headphone jack underneath.

This is most of the easy level things you can try/rule out for now.
 

StompyChar

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Just to confirm you are using the front headphone jack correct? Do not use the RCAs on the back for now.
While plugged into the headphone jack- Try to play around with the volume slider to see if it helps in any way, you could also add a small amount to the slider pot as well (assuming you have the top shell taken off)

If this doesn't work I'd consider de-soldering the wires that are tapped off the headphone jack underneath.

This is most of the easy level things you can try/rule out for now.

Well how incorrect can I use a frond headphone jack?
Stick a 3.5mm headset in it and voila right?

Regardless, I disconnected the RCA (cables) and simply had the headphone jack in with the same results as before.
The top shell is indeed off though the RCA adaptation is still connected by wires so it's sorta just resting behind it.
Messing with the slider has had no results.

I've currently not got the means for soldering, so I'll have to shelve the project unfortunately until current covid rules allow me to head over to a friend with all sorts of equipment again.
Thanks for the help sofar, I can at least play the games without sound, that's further then I've ever been before.
 

Neo Alec

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Someone will probably need to recap the whole audio circuit.
 

ballzdeepx

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Well how incorrect can I use a frond headphone jack?
Stick a 3.5mm headset in it and voila right?

Regardless, I disconnected the RCA (cables) and simply had the headphone jack in with the same results as before.
The top shell is indeed off though the RCA adaptation is still connected by wires so it's sorta just resting behind it.
Messing with the slider has had no results.

I've currently not got the means for soldering, so I'll have to shelve the project unfortunately until current covid rules allow me to head over to a friend with all sorts of equipment again.
Thanks for the help sofar, I can at least play the games without sound, that's further then I've ever been before.

Sorry, I meant to say in my post to add some deoxit to the volume slider/wiper.

If that doesn't help then its going to be chip or cap work most likely...
 

StompyChar

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A clear moment of instructions unclear got x stuck in y.

But It's fine, even that didn't work so I guess I'll have to hope my techincal inclined friend can help with a soldering job.
One question remains; how come the console's sound is perfectly fine during the initial Neo tune?
 

ballzdeepx

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Last edited:

StompyChar

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Guessing it may be somehow related to this and the way it's pulled (all I can do is guess for you at this point sorry)
https://wiki.neogeodev.org/index.php?title=YM2610#Multiplexed_ADPCM_bus

How many different games have you tested with/do you own out of curiosity?

No need to apologise, I've learned more and gotten further then I'd have gotten alone sofar.

I own 7 different games (mix of EU, US and JP) and all of them have the same issue.
That's the first thing I did myself, cleaning the cartridges and testing if it was down to a single game.
Unfortunately it's all of them so that ruled that out.
 

DaisyAge

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Someone already said this but it may just need a recap. On the 161 multicarts there's a fix for this same issue that involves adding capacitors so I'm betting that a recap would do your AES some good.
 

StompyChar

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So, seeing as there is a modification applied to the system, can anyone here tell if this was a kit job or something homemade?
I might need to find a wiring diagram or learn about such things to see if I can revert, fix or need to change it entirely down the line.
 

Neo Alec

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So, seeing as there is a modification applied to the system, can anyone here tell if this was a kit job or something homemade?
I might need to find a wiring diagram or learn about such things to see if I can revert, fix or need to change it entirely down the line.
Homemade. Doesn't really matter. If it was a kit, it would've just been a set of resistors and some jacks. Looks easy enough to reverse - just desolder and remove everything. Jacks are already drilled into the case though, so might as well keep it if the video works.

It sounds like the audio issue might only be impacting the ADPCM samples, which is why the Neo Geo logo sounds fine.
 

StompyChar

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A little bump to let you guys know that the issue has been fixed.

I visited a technological savvy friend last weekend and together we stripped the console again and checked it over.
He found that the audio mod wires leading underneath the board were somewhat pinched and making ground or contact somewhere along the way.
After re-soldering those two wires the sound returned to it's perfectly crisp and perfect state.

Thank you all for who helped diagnose and try and fix this together with me!
 
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