Neo Geo AES sound buzzing

[Rudybegga | 48]

I traded for a Neo Geo AES some time ago on the ole NA forums.  I think it's some sort of AV modded system. 

Anyhoo, I plug it into my hdtv and finally play around with it a few years ago.  The visuals look great, but there's a very noticeable buzzing noise that comes in with a different volume on each scene change. 

Is it because I'm using an HDTV and not a tube tv?  Is it because I'm not putting it through a sound system with a ground?  Any help is appreciated, or if pics would help, let me know what I need to photograph.

Edit:. I might have posted this in the wrong forum.  Posted in collectors questions forum instead...

 

Edited January 12, 2023 by Rudybegga

[a3quit4s | 4,096]

This is probably more the right forum but others may be able to help you out there as well. Is this one of the models that has a headphone jack? If so give the headphone Jack a try and see if the buzzing is still there. Since you don’t know who did the mod, without it in front of me I’d probably see how the mod is tapped in to the audio and maybe even take the mod out and see if the issue still persists. I don’t have a whole lot of experience with Neo Geo so hopefully someone here has seen that issue before. 
 

edit: depending on your board revision this guy went above and beyond has has the same problem you describe. 
 

https://www.neo-geo.com/forums/index.php?threads/the-audio-issue-of-aes-revision-3-4.198891/

Edited January 12, 2023 by a3quit4s

[Rudybegga | 48]

Wow!  Thank you!  Bookmarked.

I'll get a few pics and try it later on another tv and with headphones.  Honestly, if there's a way to not have this happen and not go through the pain of sending it in for repairs, I'll do it.

[Rudybegga | 48]

Yeah, there's a headphone jack!

And I think it's an S Video AV output

 

[darkchylde28 | 1,546]

4 hours ago, Rudybegga said:

Yeah, there's a headphone jack!

And I think it's an S Video AV output

 

That's definitely not an s-video port.  It looks like an 8-pin DIN connector, which, if I had to guess, is likely the original video-out that the system was designed with.  The model 1 Sega Genesis has the exact same sort of port for exactly that purpose (composite-out).

[Tanooki | 4,932]

That's what it used, basically it's the common cable the Genesis and I believe either TG/PCE used too. 

[darkchylde28 | 1,546]

@a3quit4s, FYI, he posted this detail in his other thread for this he created in Collector's Corner.  I replied to him there, but it looks like he may be using the stock 8-pin DIN AV out based on the photo, and I suggested he use electrical contact cleaner or DeOxIt to flush out any dirt and oxidation that might be present in the port, which could absolutely cause the issues he's describing over composite.

3 hours ago, Rudybegga said:

I posted a pic in the other forum.  S video into red white yellow.  Not HDMI.

 

[darkchylde28 | 1,546]

1 minute ago, Tanooki said:

That's what it used, basically it's the common cable the Genesis and I believe either TG/PCE used too. 

Are they pin compatible?  I know that port got used a lot in the 80s, but not everything used the same pinout, and trying to connect up an adapter for one system to a different one that happens to have the same port can result in some unfortunate circumstances (sometimes even to the point of frying the system, and/or the screen it's connected to).

[a3quit4s | 4,096]

I agree with giving everything a good cleaning with IPA, I’d still test the headphone port though. If you hear it in the headphone port it could be the audio circuit and then depending on the board revision you may be running on the link I posted earlier. If it seems difficult for you I can vouch for @Nes Freak if he is still around doing repairs. 

[Tanooki | 4,932]

@darkchylde28 Yes, the model 1 a/v cable which also works on the master system has the same pinout required to work on an AES.  I couldn't remember which model, fast search pulled up the toxic neo geo forums explaining which works.

 

With that I do believe there were s-video cables as well possible, so maybe a cleaner option yet.  Beyond that you're into the modern weeds of the expensive retrovision junk and the rest.  But in the end it can't be the a/v cable for Genesis/32X MODEL 2&3  Must be MODEL 1.

[Koopa64 | 51]

No version of the Neo Geo AES has S-Video output, that's strictly an aftermarket modification only.

No, the PC Engine/TurboDuo etc systems have a different composite AV cable compared to a Genesis or Neo Geo. The PCE systems have stereo audio output on their 5-pin DIN socket, this isn't directly compatible with a Genesis-type cable.

The AES and Genesis Model 1 have electrically compatible 8-pin DIN sockets, but the top two pins are not in the same physical places. People usually describe it as the Neo Geo uses a C-shaped pin arrangement, whereas the Genesis and SMS are U-shaped. This is only a problem for RGB cables, you can use composite cables freely across these same systems.

As for buzzing in the audio that changes depending on the visuals, that sounds to me like an HDTV-related problem, perhaps there's a lack of noise isolation between the audio and video. I would highly recommend testing your AES on a proper CRT TV before doing any needless work on the console itself. Analog AV nearly always has at least a little noise, but it's not uncommon for HDTVs to have very cheap analog decoding hardware.

Just to rule out something dumb, are you sure you're not using some sort of stereo audio + composite cable on your AES? Like the PC Engine Duo AV cable, which is a 5-pin DIN cable with stereo audio, that would definitely give you buzzing audio.

Edited January 13, 2023 by Koopa64