AES RGB Mod - Question for Rockstarrunner and/or MKL (or anyone else)

I've recently modded my late model JPN AES (serial 200k+) and the lines which I thought I could live with are now starting to give me the shits. Now I've only just discovered this RGB mod and am tempting to do this on my Neogeo.

This is the thread I've been looking at

To be honest, the reason I bothered with the S-video mod in the first place is that I wasn't sure if my TV could handle RGB directly. It's a new model Sony HDTV and although it doesn't have a Scart plug in the back, it does have 5x RCA's which is used for RGBHV. I experimented a little and made up a circuit that split the composite sync signal into H&V syncs (using a LM1881N sync separater) and to my surprise the TV displayed the image! I was stoked because I thought this input was only for progressive signals. At the moment the image through RGB doesn't show the lines as much, S-video is more sharper though.

Anyway back to the point of this thread. Do I have to sacrifice the composite output? Will the S-video also be gone if I remove the 4 capacitors and 3 resistors from the board?

If S-video is still available, I can run that to the composite RCA plug internally. This is just so I can use my Neogeo on other TV sets if I ever have to.

Hey,
Well okay, I can tell you that doing the rgb bypass makes the picture perfect

Anyways, the way the rgb bypass works is to obviously supply a direct connection from the video source to the output, so nothing interferes with the signal and thus degrades it. The higlighted components are removed to break the path of the original signal.

I have not looked closely at the s-video mod, but the path to av out pins is broken by the removed components... seeing as the s-video mod uses it's own output it should still work I guess... MKL could say for sure. However, composite IS sacrificed doing the mod in the way it is specífied in that thread.

Perhaps though mkl could suggest some method of switching the video out... perhaps by doing the bypass to some switch mechanism, and taking the composite video there to, and then having a switch on the back of the machine to choose the output... this is just a thought, as MKL is the man behind this mod, i'm simply his typist I think this might be a sound idea, if you want to be able to use it on non rgb/s-video capable televisions.

Thankyou very much for the reply Rockstar.

I had another thought which I hope you can help me with, would it provide the same outcome if I simply cut the traces on one side of the components that need to be removed instead of removing the components totally? I've included a picture of where I think the traces can be cut (marked in red). I may be totally off the mark so please tell me if I'm wrong.



I know that I have to remove to link to the old components that would interfere as I want a clean RGB signal. Composite doesn't have to come out of the AV port as I installed a composite jack when I did the S-video mod. I can simply make it run through that and keep the AV port strickly for RGB.

Cheers

I may have told rockstarrunner to cut the resistors because I use to disable the encoder as when you have RGB you just don't need composite. Actually I go so far as to physically remove all the components that are useless after the mod:

http://img.photobucket.com/albums/v65/nassivera/stuff/AESparts.jpg
http://img.photobucket.com/albums/v65/nassivera/stuff/AESsolder.jpg

But if you want to keep composite out you can. In that case you only have to break the RGB lines after they come out of the encoder. And you can do this by cutting the traces instead of removing components (although this is easier). However in that pic I see that you cut the Red line twice, before and after the 470uF cap and that you didn't cut the Green line, so be careful. As for composite out, you can still have it through the A/V port but on that revision board you have two composite out pins and no sync (unlike early revisions): the pin where I soldered the yellow wire and the pin below it are connected together and are both composite, so if you want to run sync to one of them and composite to the other you have to separate them (by cutting a trace). On a side note, I use one of these two pins and the audio one for stereo: this way you don't have to alter the shell of the console by adding jacks.

Thanks MKL, I found where I made the mistake in regards to the capacitors.

Would you mind just checking this for me..



I think I have the points right that you mentioned (about keeping composite). I wasn't sure what you meant by the pin directly below are both composite. Which other pin are you talking about? The one on the encoder or or the AV port pins?

If I have it wrong, would you mind posting a quick pic of where the extra wire has to go.

Thanks for all the help.

OMG! The picture is absolutely glorious!

I was totally off in that last post, here's a pic I took once I was finished.



I changed my mind and desoldered the capacitors instead. At least that way it doesn't wreck the board in any way.

The red mark is where I cut the trace for composite. Weird thing though is that I get composite out from the jack I installed but not from the AV cable that came with the Neogeo?? All I get is a white screen.

S-video still works too, not that I need it now You guys rock. Thank you so much.

This is the A/V port pins on solder side:

C........GND........A
.....G...........5v
S..........B..........R

You (like me) have soldered sync (yellow wire) to C (composite), that's why you don't get any picture when using the proprietary composite cable. If you want to have composite out from the A/V port, solder the sync wire to S. But in this case you'll have to break/cut the composite line that from the encoder goes to S: this is what I was trying to say in my previous post: pins C and S are both composite on this board. If you check with a multimeter you'll see that C and S are connected together. Well, not anymore in your case since you cut a trace. But S is still connected to the composite line coming from the encoder, so you have to cut that trace somewhere if you want to run the yellow wire to that pin (S). And you have to reconnect the composite trace to pin C that you cut.

MKL - Thanks for supplying me the wrong information

I got eveything working now. I swapped the yellow wire, repaired the trace and cut the other one leading to the sync pin.

I don't know whether it's just me, but I think the picture is even better than it was as now it's receiving the true sync signal. Before I used to see very faint dots on certain colours (pinks and browns mainly). These have gone totally!

So obviously when you had yours wired up with the sync going to the composite pin, you got no picture?

Dreamcazman said:

So obviously when you had yours wired up with the sync going to the composite pin, you got no picture?

Click to expand...

Since I removed the encoder altogether there was no possibility of getting any picture other than RGB. I used the (former) composite pin for sync because Neo scart cables use the composite line for syncing. This way you can keep using the old cable without having to make a new one...

MKL said:

Since I removed the encoder altogether there was no possibility of getting any picture other than RGB. I used the (former) composite pin for sync because Neo scart cables use the composite line for syncing. This way you can keep using the old cable without having to make a new one...

Click to expand...

Ahh ok, I didn't know that.

Thanks for all your help

Just a question, with this mod you bypass the 1145 sony encoder?
Or anything else?
Thanks.

JAMMASLOT said:

Just a question, with this mod you bypass the 1145 sony encoder?
Or anything else?
Thanks.

Click to expand...

Yes, you do bypass the encoder, that's the whole point of the exercise. The encoder wrecks the RGB signal in the late model Neo's and this mod allows you to tap into the RGB lines before it gets to the encoder thus making the picture quality pretty much perfect!

Yes, i can believe it..
Only mvs here, but i can remember the quality of the 1145 composite.
This encoder is very old, now...

rgb bypass aes 3.5

MKL said:

Since I removed the encoder altogether there was no possibility of getting any picture other than RGB. I used the (former) composite pin for sync because Neo scart cables use the composite line for syncing. This way you can keep using the old cable without having to make a new one...

Click to expand...

hello i m frenchie and i have a problem with my aes 3.5 serial 112 993 , i got the rainbow effect , i promise it s true , and i have tested with other tv and the effect stay !!!!! i read the differends threads but no one for 3.5 help me please , and more i not alone in this way ,
my email bemathis@wanadoo.fr
msn mosdefben09@hotmail.com
thanks

Can you stop posting in every RGB bypass thread. Just wait for MKL to answer the other thread.

MKL said:

Since I removed the encoder altogether there was no possibility of getting any picture other than RGB. I used the (former) composite pin for sync because Neo scart cables use the composite line for syncing. This way you can keep using the old cable without having to make a new one...

Click to expand...

Xian Xi said:

Can you stop posting in every RGB bypass thread. Just wait for MKL to answer the other thread.

Click to expand...

ok