Neo Geo AES low-serial 3-2 board with dim picture

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ASDR
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Neo Geo AES low-serial 3-2 board with dim picture

Post by ASDR »

Hi all,

I have a 3-2 revision low-serial AES that has a very dim picture. I'm trying to fix this and found this helpful post by RGBSource:

viewtopic.php?p=1269037&sid=389c30b5c3e ... e#p1269037

I'd love some advice on my particular machine. Here's a picture of the whole board and a closeup of the relevant area around the video encoder:

https://imgur.com/a/NzEh9

Some observations:

- Seems like on the output side the 68Ohm resistors and 100uF caps have already been replaced with 75Ohm and 470uF components. Strange, this system was supposed to be untouched...
- On the input side, we still have the 0.1uF capacitor
- Note that the 2.2kO labeled resistors in the voltage divider are actually 1.5kO. WTF?

Now, how do I fix this. Qs:

- Should I first try replacing the odd 1.5kO resistors with on-spec 2.2kO or go straight for 3.0kO like in the later board revisions?
- Is there any point in doing the 0.1uF -> 1.0uF capacitor swap on the input side if I have no complaints about the image apart from the brightness?
- Anything else I'd need to consider / watch out for?

Any advice much appreciated!
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