32X S-Video Mod

[tenchibr]

Does it have the full picture scrolling around with weird colors, or a generally dark screen with blue/red/etc color kind of warping/scrolling around randomly? (if it's the latter, it sounds like the TV isn't getting any luminance signal, so the problem would be in the luminance portion of the circuit -that sort of odd, out of sync picture is exactly what I get on a flaky S-video switchbox that has trouble making contact with the luminance line of S-video cables )

The opposite problem would be lack of chroma, but that would just create a b/w image with proper sync. (luminance carries sync, so no luma, no sync -well, unless you intentially run composite sync to the luma pin, then you'd get proper sync with chroma but no luma -which would look really weird )

Actually today I got a still image without scrolling like crazy but red colors only, but if I try to adjust the S-Video cable, jerking it around causes the screen to jump like crazy and then you see a combination of red and purple (red + blue, so I think the red is continuous); I never see it black & white.

Worth mentioning, I am using the SEGA CD BIOS for this; so the image doesn't really change drastically at all other than the SEGA logo moving around. And hooking the S-Video cable up to the Genesis makes a flawless signal.

Edit: I decided to test something else out and I found out I am dumb. I was like "maybe it's the Patch cable huh?" so I hooked up the composite to see, and then I realized it was giving the same red and purple signal, so it seems my patch cable is dead. The final nail on the coffin was hooking up the 32x cable to the Genesis 1 to 32x cable directly, skipping the Patch cable, and the signal was perfect (as perfect as composite can be...)

But thanks for trying to help; buying a new cable and will post updates.

[tenchibr]

Ok, just got a message from Gametrog that my 32X Mixing cable is on the way; but in the meantime, I recorded this video to have others confirm my suspicion that it is indeed the cable, and not a mess-up on my soldering, for example:

[tenchibr]

I finally got the new cable, but I'm still having the same problem... Is it possible I damaged the 32X when I tried to mod it?

Edit: I decided to try to turn it on without the top cover like the OP did, and that "fixed" it; in other words, the mod is fine, but when I put the cover it does something that causes the bad signal, like I'm crushing the wires somewhere. I put it back on, but tried to tighten just enough to be sturdy, and it's fine now...

On the other hand, I'm glad the Patch cable wasn't a waste, because my original one was also part of the problem.

I do have one last question though; the image is darker on the 32X than the Genesis one; is there any way to increase the brightness with resistors?

[Ace]

Use weaker resistors. I suggest using 75ohm resistors or as close to that as you can get.

[tenchibr]

Use weaker resistors. I suggest using 75ohm resistors or as close to that as you can get.

I'm hoping that's the sweet spot.

[tenchibr]

Closest thing they had at Radioshack was 68ohm; but it worked. So I wouldn't recommend anyone to use 100ohms, but your TV can vary.

Thanks for the help; unfortunately I agree with you Ace, and the 32X S-Video isn't as good as the Genesis one; but it's still superior to 32X Composite for me; the only difference from the 32X signal to the Genesis (HDG Model 1) that I see is that 32X's is slightly blurry, but I think that's the video encoder's fault. Even though it's a tiny bit blurry, it's sharp enough to enjoy playing it on my HDTV (which does not support 240p signals on Component - I have a SCART-to-YUV that doesn't work with it...)

And also, the video encoder from the 32X seems to suffer the same vertical line issue that the HDG Model 1 has with the S-Video; but nearly not as bad.

[villahed94]

NecroBump!


I suppose that the remaining pins are output signals, from where resistors should be soldered, right?
What about changing luma value down to 27ohm, while still keeping 75 ohm on chroma?

[ApolloBoy]

So let me get this straight, if I follow the mod as shown on the first page but use 75 ohm resistors instead of 100 ohm ones, this will work? I occasionally get PMs asking if I can do 32X S-video mods and I would love to see if this actually works.

[villahed94]

Supposedly, yes. However, I'm going to use different transistors. The 2SC1741A s have worked just fine for my Genesis video mods, providing clear and crisp image.

[ApolloBoy]

I just tried this mod today on my brother's 32X and I saw absolutely no difference between this and composite, it was probably the blurriest S-video output I've ever seen. Needless to say I won't be trying this mod again since it isn't worth it.

[villahed94]

IMO the filtering the 32X does is pretty bad and blurries the image. I'm going to try with a different transistor/values or even use the raw, unfiltered signals.

[Drakon]

*bump*

The luma filter is what was screwing up the image. I disconnected the luma output pin from the filter and suddenly the image was nice and sharp.



Disconnecting the filter made the sharpness go from this...



to this:



Chroma didn't need an amp...it didn't need anything actually.

[villahed94]

It looks pretty good, but I prefer to out a new encoder(CXA2075) on top of it.
I have a problem though with it. White is not really that white, but as a yellowish white...

[ApolloBoy]

White is not really that white, but as a yellowish white...

I honestly don't see a real difference. So this all comes down to disconnecting a jumper then? I'll have to start offering this if you don't mind...

[TmEE]

Disconnecting the signal results in no Composhit output though.