Genesis CDX RGB

[Segasonicfan]

OoooOooh, they are the same! lol.  So would this mod work for the CDX??
http://www.gamesx.com/rgbadd/genesis3.htm

That would be fabulous.  

THEN I could finally complete my CDX Ultima!

-Segasonicfan

[Segasonicfan]

oh, and one last question....should I add the resistor and capacitor to the RGB lines?  I just want to make sure I have the very finest quality, and after following the traces I noticed there isn't any resistors or capacitors...

Thanks for all your valuable help!

-Segasonicfan

[NFG]

Chances are the resistor + cap are either already present, or the RGB comes from somewhere else.  I've been told the Gen3 has RGB pulled from a Sega chip, not the CXA1645.

And if it works for the Gen3, of course it will work for the CDX if the chips are the same.  =P

[D-Lite]

No, no, no.  This is what has what as far as I can tell:

Gen 3:  CXA1645 chip (and Lawrence, the RGB is directly off the Sony chip)
CDX:  MB3514 which is pin compatible with the CXA1145, NOT the 1645
Gen 1:  CXA1145 (so far, haven't opened another yet)

So no the Gen3 mod will not work for the CDX.

You need to do the full mod as shown at neogeousa with the MB3514 or 1145 chips.

[Endymion]

The Genesis 1 I opened up the other day has a Sony CXA1043P. Same as 1145?

[NFG]

I couldn't find anything on the 1043P, except (as usual) some chinese sites offering to sell me a PDF.

[D-Lite]

couldn't find anything on the 1043 either.  Probably is pin compatible with the 1145, but maybe doesn't have Y and C out?

[D-Lite]

Update:

Just opened up an X'Eye.  And lo' and behold, a Sony CXA1145.

So, guess multiple versions exist for this too, huh?

[Segasonicfan]

why would the Genesis 3 mod not work for the MB?  the only pin difference between the MB3514 and the CXA1645 is that chroma and luma outputs are swapped.  That is according to Sony's official diagrams: http://www.gamesx.com/rgbadd/cxa1645.pdf  Chroma is 16 and Luma is 15.  Is there some reason why adding the one resistor and capacitor would not make an S-Video output?  I tested the output without these and got a decent picture, it just had some thin lines through it.  I imagine the resistor and capacitor will fix that.  I'll likely test it tomorrow...

[Endymion]

why would the Genesis 3 mod not work for the MB?  the only pin difference between the MB3514 and the CXA1645 is that chroma and luma outputs are swapped.

Well I would guess that the reason would be the same reason that you can't get the mod to work on an 1145 without doing all other kinds of crap.

[D-Lite]

why would the Genesis 3 mod not work for the MB?  the only pin difference between the MB3514 and the CXA1645 is that chroma and luma outputs are swapped.

Well I would guess that the reason would be the same reason that you can't get the mod to work on an 1145 without doing all other kinds of crap.

Well, to be specific, the Genesis 3 uses the CXA1645 chip which has better Y and C out.  If you check the datasheet for the CXA1145 (or the MB3514 for that matter), you'll see a bunch of other schlock involved.  Basically, that other "stuff" is a delay and a Band Pass Filter, which are included inside the 1645 (again, referring to the datasheet).  So, without the delay and BPF, the image will still work but won't be optimal and will probably be noisy (as in the lines you see).

Believe me, the difference in the mods is quite noticeable in terms of image quality.

[Segasonicfan]

could i take out the MB3514 and out a CXA1145 in its place since they have the same outputs and inputs?  I dont want to do that unless im sure itll work though....cause its a risky thing with a CDX.

-Segasonicfan

[D-Lite]

could i take out the MB3514 and out a CXA1145 in its place since they have the same outputs and inputs?  I dont want to do that unless im sure itll work though....cause its a risky thing with a CDX.

-Segasonicfan

??  Why would you want to do that?  They're the same chips.  You'd want to swap in the CXA1645 chip if anything.  But why not just do the mod done on the Neo Geo AES?  That's a hell of a lot easier than replacing an SMT chip.

[Segasonicfan]

sorry, i meant the 1645.  It doesn't matter now though.  I teseted the MB3514 with the Genesis 3 mod here on GameSX adding 75 ohms and 220uf and it worked BEAUTIFULLY.  I got an incredible, crisp picture and the finest looking Sonic 2 I've ever seen on my television  It sure beats the hell out of composite and I can't imagine the Neo Geo AES mod working any better.  I also got a second first-hand opinion, and my friend agreed it was a vast improvement over composite and the video looked great.  The vertical lines aren't on the screen anymore

I recommend this mod to anyone with a CDX or Genesis system with the MB chip!!

-Segasonicfan