Neo Geo AES 3-5 RGB bypass w/ THS7316 amp issues. [SOLVED]

Joined
Mar 28, 2020
Posts
20
EDIT: Got the issue resolved, see second post if interested.

Well, I got around to working on the RGB bypass for my revision 3-5 AES over the weekend, and I wrapped it up this morning. I used instructions found here to build a video amp with a THS7316 chip; I've used these in my N64 with good results and I had some sitting around so I figured why not? I got the board all wired up with the amp and got it installed in the AES.

When I fired it up through the OSSC, I wasn't too impressed with the results. I had to tweak the LPF for the sync and the video in, but after that I was basically stuck with the jailbars yet again. Here's a pic (sorry about the quality).

It's hard to make out from the picture, but the jail bars are very pronounced now; however, it's mainly in any areas where there's a solid black backdrop (such as a title screen, like in the pic). There's also a strange reddish tint in the jail bars.

Here are a few pics of the RGB amp installed in the AES and the amp itself:

Amp installed in the AES.

Detail of the amp board.

Anyone have any ideas what might be causing this? I pored over the amp schematics and build, so I'm 99.9% certain that it's not to blame. Would a "standard" RGB bypass have better results in this scenario (something like Xian Xi did over on his JNX page)? I'm not a complete videophile and I don't demand utmost perfection from the video output (which is why the THS7316 amp might be a bit overkill), but I *would* like to eliminate the jail bars from the signal and get a solid RGB output from the console.

Any insight or help would be greatly appreciated. Thanks in advance!
 
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Joined
Mar 28, 2020
Posts
20
You know, I feel like a bit of a dum-dum every time I post on here. I figured out the problem about ten minutes after making the thread: the location the amp board is installed is not ideal. There's a support leg that comes down from the top half of the AES shell, and it was putting pressure on the RGB amp sub-board. I re-positioned the board inside the AES, and voila! No more issues with the output. In fact, the video quality is absolutely amazing. It's every bit as good as the Neo Geo CD I have, and that's saying something right there.

Many apologies for jumping the gun on asking for help, but if you were curious and clicked through then hopefully you can now get closure for this issue.
 
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