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Thread: RGB bypass mod

  1. #1
    Ninja Combat Warrior
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    RGB bypass mod

    I'm thinking about doing the rgb bypass mod and have a few questions and things I'd like to clarify.

    First of all I'm in the UK so I'm connecting my aes to the tv using a scart lead. If this outputs rgb do I really need the rgb mod seeing as I have a low serial number console? Or is it the case that the Video encoder chip degrades the rgb signal and bypass would improve the picture by using the orginal rgb signal?

    I've been reading these threads:

    http://www.neo-geo.com/forums/showth...gb+mod+picture
    http://www.neo-geo.com/forums/showth...hlight=RGB+mod

    These are for series 5 to 7 boards though and I have a series 1 board. Could someone please show me the connection points for a series 1 board? I'd like to keep the composite and s-video capability if possible.

    I may be totally off the mark with this last question but it's just a thought I had:

    If I wanted to install seperate rgb sockets in my aes instead of using the existing A/V port would I just need to solder the rgb wires to the corresponding jacks instead of the pins on the A/V port? If so where would the sync wire go? I'm just thinking this would still allow the composite signal to be used from the A/V port if needed. I guess this would require me to make up a new cable to connect the rgb sockets to scart though...

  2. #2
    Paris-Dakar Rally Driver
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    I wouldn't bother with the RGB mod on your console as it's great already! The video encoder doesn't seem to degrade the signal as much as it does in the later models (like mine)

    Regarding that last question, the easiest would be (if you want RGBS outputs via RCA connectors for example) to solder 4 pieces of wire from each colour and sync on the underside of the board where the AV jack is and connect the other end of each wire to the centre pin on the corresponding output jack. The ground on each plug can be all joined together and then soldered to a common ground on the board somewhere.
    Last edited by Dreamcazman; 02-02-2005 at 03:59 AM.

  3. #3
    Benimaru's Hairdresser
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    RGB mod....

    I did the RGB mod on my home system, 100 % better,sharper,clearer picture as good as a MVS picture after the mod...
    I used the same socket and scart cable as before..
    MKL on this forum is the man with the knowledge on this mod...
    Fight war not wars.

  4. #4

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    If you want to do the RGB mod and keep the composite out from the A/V port, it's no problem.

    http://img.photobucket.com/albums/v6...ra/NEOAES1.jpg
    http://img.photobucket.com/albums/v6...ra/NEOAES2.jpg

    You can cut/remove the 68ohm resistors for R, G, B and sync.

    There's a row of 21 resistors, 7 for each of the 3 colours (RGB):

    http://img.photobucket.com/albums/v6...ra/NEOAES4.jpg

    Take three wires (better if coloured red, green and blue) and solder them to one (any) of the resistors of their respective colour. Solder the other end of the wires to the places where the 68ohm RGB resistors were. Better run the wires on parts side (the 21 resistors are located right on the vent slots of the bottom shell, which makes it difficult to do the job on solder side). On solder side, solder another wire from pin 10 of the CXA1145 to the sync pin of the A/V port shown below:

    http://img.photobucket.com/albums/v6...ra/NEOAES3.jpg

    And that's it. The only thing that remains is that without some resistance in the RGB lines the picture may be a bit too bright on a scart TV. 82 or 100ohm will adjust the picture for the best result. Now, you can choose where to put the resistors: inside the Neo Geo, as shown here (the resistors are covered by heat shrink), or inside the scart Plug (on the cable), it's up to you. I'd recommend in the scart plug because that way the Neo itself will output an MVS-level RGB signal and could be used in a cabinet with the right harness.

    Of course you'll need a new RGB scart cable that uses the sync pin instead of the composite pin for syncing.
    Last edited by MKL; 02-02-2005 at 04:39 PM.

  5. #5

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    Does anybody on these boards do the RGB mod in the UK? If the cost was not to much i would like to get my aes done.
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  6. #6
    Ninja Combat Warrior
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    MKL, thanks very much for your reply, much appreciated. It all seems pretty straightforward, but there's a couple of things I'm not quite sure about.

    In this photo:
    http://img.photobucket.com/albums/v6...ra/NEO-AES.jpg

    you've removed 5 capacitors instead of the 4 resistors. I take it that it doesn't matter where you break the circuit, at the resistors or the capacitors, but why did you remove the 5th capacitor? Did you want to stop the composite output on that machine?

    Also, you said I would need to make up a new scart cable using the sync pin instead of the composite pin for syncing. If I soldered the sync cable from pin 10 of the CXA1145 chip to the composite pin on the A/V port I take it that would allow me to use the orginal scart cable? I'm just thinking that would be easier than making up a new cable. Then I could just install a composite jack in the shell and provide a composite output that way.

    Thanks

  7. #7

    MKL's Avatar
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    Quote Originally Posted by Adamaki
    In this photo:
    http://img.photobucket.com/albums/v6...ra/NEO-AES.jpg

    you've removed 5 capacitors instead of the 4 resistors. I take it that it doesn't matter where you break the circuit, at the resistors or the capacitors, but why did you remove the 5th capacitor? Did you want to stop the composite output on that machine?
    On that system I ended up removing the whole circuit. When I took that pic I had already removed the resistors and capacitors in the R, G, B, sync and composite lines, so that system stopped outputting composite (which is useless and on early systems also very bad).

    Quote Originally Posted by Adamaki
    Also, you said I would need to make up a new scart cable using the sync pin instead of the composite pin for syncing. If I soldered the sync cable from pin 10 of the CXA1145 chip to the composite pin on the A/V port I take it that would allow me to use the orginal scart cable?
    Yes and that's what I usually do when I don't care about leaving a composite out on the A/V port.

    Quote Originally Posted by Adamaki
    I'm just thinking that would be easier than making up a new cable. Then I could just install a composite jack in the shell and provide a composite output that way.
    Do you even need composite? I wouldn't bother...

  8. #8
    Ninja Combat Warrior
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    Thanks MKL, it's all clear now. As soon as I get round to doing the mod I'll post a pic up here and you can all see how bad/good my soldering is!

    Do you even need composite? I wouldn't bother...
    I probably won't bother with composite on my system but I've got another one that I'm going to mod and sell so I think it's best to keep as many video formats as possible in case I end up selling it overseas. Like Jeff said a while ago it'd be annoying for someone in America to buy it and find it has no composite or s-video output. Anyway, it's always good to know how to do all the mods for future reference...

  9. #9
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    ok I just tryed the rgb mod without success, I only get audio now.
    damn I suck at soldering.

    I'm using ide-cables, should be good?

    heres a picture

    Also I used the 3 resistors that I desoldered from the neogeo

    I'm going to have to redo this all over again.
    Last edited by Paiku; 04-12-2007 at 10:32 AM.

  10. #10
    Starks is always out. tony starks's Avatar
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    Quote Originally Posted by rudekid
    Does anybody on these boards do the RGB mod in the UK? If the cost was not to much i would like to get my aes done.
    Dude, chaoticjelly is based in the UK, I would recommend him, just sent mine to be modded. PM him and he will give you more details on cost and what not.

    Starks out....

  11. #11
    Galford's Armourer
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    Quote Originally Posted by tony_starks
    Dude, chaoticjelly is based in the UK, I would recommend him, just sent mine to be modded. PM him and he will give you more details on cost and what not.

    Starks out....
    Two years too late my friend

    Check the start date for this, the poster before you obviously bumped this old topic in reference instead of starting a new one.

    I had mine done by ChaoticJelly btw, you'll definately enjoy your system when he's done.

    Olly.

  12. #12
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    Yeah sorry I should have made a new thread instead

    anyway I'd definitly send this to someone who can mod like a pro. I've really screwed up now, thought I could handle this simple looking mod

  13. #13
    Starks is always out. tony starks's Avatar
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    Quote Originally Posted by TrueTrials
    Two years too late my friend

    Check the start date for this, the poster before you obviously bumped this old topic in reference instead of starting a new one.

    I had mine done by ChaoticJelly btw, you'll definately enjoy your system when he's done.

    Olly.

    My bad

    starks out...

  14. #14

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    Quote Originally Posted by Paiku
    ok I just tryed the rgb mod without success, I only get audio now.
    damn I suck at soldering.

    I'm using ide-cables, should be good?

    heres a picture

    Also I used the 3 resistors that I desoldered from the neogeo

    I'm going to have to redo this all over again.
    The wiring seems to be correct as far as that low res pic allows to see. And let's assume there are no shorts and cold joints and that the scart cable is wired correctly. The problem then must be the three resistors you used which are 6.8k, i.e. way too much. I suggest you to first try with no resistors, you can add them later if you're not happy with the picture. Recommended values between 82 and 120 ohm.

  15. #15
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    Yeah, I feel like a dumbass now, I was so desperate to get that pure rgb signal that I jumped into it right after reading these treads.

    I'm gonna try without resistors first and do a better work with the soldering.

    thanks MKL

  16. #16
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    Ok, re-soldered without resistors and got this scrolling screen without a cart in the system.


    What do you think the problem is?

    I'll probaly try to find someone who can solder better than me next try
    Last edited by Paiku; 04-14-2007 at 01:34 PM.

  17. #17

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    Make sure the cable is wired in accordance with the mod you did: if you have chosen pin 7 as sync but the cable has sync on pin 3 you have to correct this (either on the system or in the cable):

    http://img487.imageshack.us/img487/3626/aesrgbea5.jpg

  18. #18
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    icon29.gif

    Weeeehaaa!

    It turned out successful this time

    The screen is perfectly clear, not sure if I even need the resistors.

    Man what a relief, this was the first time I ever soldered for real, this made my week

    Thanks MKL for all the help and info that made this possible for a noob like me

    I can't wait for SSVS now!

  19. #19
    Timid Neo Newbie
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    icon19.gif

    Hi, I want to try this mod on my japan AES with 128869 serial number (yes, it does have those crap rainbow effects), but i have a few questions:

    1) If I do something wrong, is there a way of reversing it?

    2) Can I "burn" my AES doing the wrong connection?

    3) My TV need to have some sort of "restriction"?

    and finally,

    3) When I do the mod can I use the "good old" A/V cable?

    That's all,

    Thanks for any help in advance!
    Last edited by Golgo13; 12-09-2007 at 08:41 PM.

  20. #20
    Cheng's Errand Boy
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    Quote Originally Posted by Golgo13
    1) If I do something wrong, is there a way of reversing it?
    2) Can I "burn" my AES doing the wrong connection?
    3) My TV need to have some sort of "restriction"?
    4) When I do the mod can I use the "good old" A/V cable?
    Hey,

    Well,

    1) - If you are careful with your solder joints, then you shouldn't really have too many problems. If you attach the resistors onto the bottom of the board make sure that the body of the resistor doesn't come into contact with any metal points, or a short circuit could be created. It would be preferable to heatshrink the resistor leads.

    2) - I don't think so, you may just get some strange effects on the screen, for example weird colours if you connect the wrong colours to different colours.. again, if you are careful this shouldn't be a problem.

    3) - Does your TV have an RGB SCART socket? I believe that is VERY rare in Brazil. I'm not sure what you mean by 'restriction', please elaborate..

    4) - Yes, you can still use the old AV cable after you do the mod.

    If you think that it's too difficult, I do have a tech-guy friend in Brazil that could probably help you out - just give me a PM and I will put you in touch with him. I think he may be registered on these very same forums too...

  21. #21
    Timid Neo Newbie
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    Quote Originally Posted by chaoticjelly
    3) - Does your TV have an RGB SCART socket? I believe that is VERY rare in Brazil. I'm not sure what you mean by 'restriction', please elaborate..
    Thanks for the quick reply, chaoticjelly

    Now, here's the problem. I don't know if my english is too bad or I'm just a noob with all this electronics "slangs", but I really don't know what RGB SCART socket means. I've tried to understand reading a lot of threads here but no use. How can I tell if my TV have an RGB SCART socket, is this some kind of different 'input' like the S-video or component or just an internal thing? If this helps, My TV is a CRT Samsung 29" slimfit. It's pretty new actually.

    The real thing is: When I do the mod, Am I still going to use all the same cables and connections that I've used before the mod?

    Thanks in advance and sorry if I bothered you in some way.
    Last edited by Golgo13; 12-10-2007 at 08:08 AM.

  22. #22

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    This is the wrong thread for you. The RGB bypass mod is not supposed to improve the composite video (or even the s-video) output but just the RGB output. In Brazil you don't have scart TVs. They're not rare, they just don't exist. Hence, you shouldn't bother with this at all. If you want to improve the composite and add s-video (or also component) out you should really put a better encoder in your system, like a neobitz or a jrok.

  23. #23
    Cheng's Errand Boy
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    Quote Originally Posted by MKL
    This is the wrong thread for you. The RGB bypass mod is not supposed to improve the composite video (or even the s-video) output but just the RGB output. In Brazil you don't have scart TVs. They're not rare, they just don't exist. Hence, you shouldn't bother with this at all. If you want to improve the composite and add s-video (or also component) out you should really put a better encoder in your system, like a neobitz or a jrok.
    SCART TV's in Brazil do exist.. but only imported!

    My tech-guy friend in Brazil uses an arcade monitor for his RGB fix..

  24. #24

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    Well if we talk about imports then anything can be anywhere... and the guy wouldn't ask what a scart TV looks like if he had an imported one...

    anyway there is a lot of misinformation around the whole bad RGB issue while in fact it's very simple:

    1) Bad RGB only affects revision 3-6 (the last and most common one, above 150xxx serial)

    2) Bad RGB shows up as a very noticeable grid pattern. Nothing else.

    3) This grid pattern is not due to different/lower quality components (as assumed on some articles) but to interference caused by board layout which explains why it happens only on that revision.

    4) It can be solved very easily without bypassing the encoder. It's just a matter of cutting 3 traces. No wires, no resistors, no soldering needed.

    Perhaps I'll make a post about this when I have a 3-6 board.

  25. #25
    Cheng's Errand Boy
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    Yeah I think it is pretty obvious he doesn't have a TV with a SCART socket if he's asking what one is.. all I am saying is that if someone imported a TV with a SCART socket into Brazil, it would be entirely possibly to obtain one.. and you could still run your AES on an arcade monitor, like my friend, in Brazil does..

    MKL have you seen this website; http://nfggames.com/games/neorgb/

    Is it misinformation?

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