hardware mods: S-Video on a 32X?

[chrisbid]

ive seen people add s-video to a genesis, but i have the triple deck genny/cd/32x biggie size combo hooked to my television.

so the questions that come up are? does the 32X have enough space to mod an s-video port, and would it work, since it takes composite info from the genesis (?)

[Flack]

ive seen people add s-video to a genesis, but i have the triple deck genny/cd/32x biggie size combo hooked to my television.

so the questions that come up are? does the 32X have enough space to mod an s-video port, and would it work, since it takes composite info from the genesis (?)

This has been kicked around before. According to all the other threads I was able to find on searching, it's "assumed" to be impossible (and no one's done it yet).

[chrisbid]

dam

i guess ill look into have my genny 3 modded then :)

[Anthony1]

Actually, there are other options.


The 32X uses the same video plug as the Genesis 2. This means, that you can use a Genesis 2 RGB cable with a 32X.


Now, you might be asking, what the heck does this have to do with S-Video?


Well, if it can do RGB, then it can do S-Video. Some people have actually made little video boxes that will convert RGB signals to S-Video. So that if you had a bunch of RGB cables for various systems, you could use all of those cables to get S-Video from those systems.



Also, even better, is if you have a HDTV. There is way where you can turn any HDTV or 480p compatible TV into a huge RGB monitor.


You would need a XRGB2 device, and a RGB cable that will connect whatever system to the XRGB2 device, and a VGA to wide band component adapater. It's kinda complicated, but it will basically turn any HDTV into essentially a huge RGB monitor.

You see, the XRGB2 upconverts the signal to 480p. But the big difference between the XRGB2 and any other upscan converter, is the fact that it actually takes the native analog RGB signal and upconverts that. Most upscan converters take a crappy composite or S-Video signal and upconvert them to 480p.

Well, garbage in, equals garbage out.

But with the XRGB2, it takes the best signal possible and then upconverts that signal. The end result, is that the picture that you get is virtually identical to a native analog RGB signal.




Now, most people use a XRGB2, so that they can play their old school systems on a Computer Monitor, with the best video signal they possibly can, but they don't realize, that if they had a cheap $15 vga to component adapter cable, they could actually use a big HDTV instead.



So, to make a long story short, if you are trying to play your 32X on your TV in the best video mode possible, your best bet might be to get a XRGB2 and a RGB cable.

Of course if you went to the time and effort to do that, then you might as well get RGB cables for all your systems, so you can play all your systems in RGB (technically upconverted RGB) on your big HDTV.

[Mangar]

What if you're big TV(Samsung 61' DLP) also has VGA inputs? I've been kicking around the idea of picking up an XRGB2+ and hooking up my Genesis and other systems to it. But was thinking more along of lines of simply plugging them in via my TV's VGA port.

Would this look better, worse, or the same as using a VGA Wide Band componant adapter?

[gcl1984]

How bout using a model 2 genny as an svideo encoder?I have a bunch layin around and figure it would be an easy and cheap way to get an svideo encoder if one of them has a 1645 in it.Just sub the signals from the 32x after cuttin the traces at the input pins .Then just add an svideo port.

[SkiDragon]

Since the 32x requires a video input (the infamous connector cable), the real question is what sort of signal is being sent through this cable to the 32x. If it is composite, then an S-video mod is much more difficult (it would require somehow making an S-video input or something). If the signal is S-video or better, then a mod seems possible. Does anybody know the answer to this question? If not, somebody could make a home-made connector cable and observe the effects as specific wires are disconnected.

I am very interested in this.

[FABombjoy]

RGB

Only way to get s-video from a 32x is to add an RGB->S-video encoder.

[gcl1984]

RGB

Only way to get s-video from a 32x is to add an RGB->S-video encoder.

So what do you think about using a genny model 2 as an encoder?
And I'm guessing ,but I think the signal from the genesis to the 32x is rgb.

[FABombjoy]

So what do you think about using a genny model 2 as an encoder?
And I'm guessing ,but I think the signal from the genesis to the 32x is rgb.

Yes, 32x uses the Genesis's RGB signal.

I'm not entirely sure what you're proposing by using a Genny 2 as an encoder.

[gcl1984]

So what do you think about using a genny model 2 as an encoder?
And I'm guessing ,but I think the signal from the genesis to the 32x is rgb.

Yes, 32x uses the Genesis's RGB signal.

I'm not entirely sure what you're proposing by using a Genny 2 as an encoder.
I have a bunch of model 2s layin around so I was thinkin if I find one that has a 1645 in it, I could cut the traces at the input of the encoder circuit in it and feed the R G B and sync signals from the 32x into it.Add a svideo output (easier than doin it to a model 1, which I have already done)and plug it in .I figure it is easier and cheaper than building the circuit from scratch.

[gcl1984]

Ok ,second model 2 I opened had an 1145 in it.I thought these things had the 1645 but after checkin over at gamesx its the model3 that has it.I only have 1 mdel 3 so I'm not gonna mess with it.
I'm gonna add svideo to this model 2 and after thats workin I'll see if I can patch the signals from the 32x into it.

[D-Lite]

The Genesis model 2 has any of these chips:
CXA1145
KA2195D
CXA1645

The CXA chips can both be used for S-Video. The 1145 requires a bit more work than just caps and resistors.

[gcl1984]

Then I'll check the rest of the model 2s I have.I prefer the ease of the 1645.Thanks for the info D.

[SkiDragon]

I did the mod for the CXA1145 chip in my Genesis 2. It was complicated but it works fine. I found the instruction at neogeousa.com

I did not know that the Genesis 2 sometimes contains the CXA1645. Are these more or less common than the CXA1145, and where can I find instructions on how to S-video mod them?

I think video mods should be sorted by chip instead of by system.

[gcl1984]

Ive also added svideo to a model 1 and an Xeye using the 1145 usindg the same instructions.Its not a bad mod but the 1645 just needs a resistor and cap added to the svideo output.I think its a 75 ohm and 220 microfared.

[D-Lite]

Ive also added svideo to a model 1 and an Xeye using the 1145 usindg the same instructions.Its not a bad mod but the 1645 just needs a resistor and cap added to the svideo output.I think its a 75 ohm and 220 microfared.
Yes all around.

Very few model 2 systems have the 1645. From what I've seen it's about 60-70% KA2195D, about 20-25% CXA1145, and 5-10% CXA1645. I've opened 25-30 of the bad boys so far and that seems to be a reliable estimate.

[SkiDragon]

I should have looked in more Genesis 2s before I did my mod. I figured the 1145 chip was the only one, besides the incompatible one.

[Kamino]

i'll toss a new question out. if this makes any sense:
The 32x basically "passes the video thru" as far as i understand.
Theory:
With an S video modified genesis, would it be possible to REPLACE the passthrough a/v output jacks with s video passthrus?
I have been trying to figure out a way to do this, but I can't find any friggin' schematics for a 32x, nor can I figure out which chip on the 32x is the VDP, nor can i figure out which chip(s)the passthrough jacks, well, pass through.

[davidleeroth]

If you can wait a few days, I should be able to tell how to get S-video out. 8-)

[davidleeroth]

So...

On the 315-5788 chip, luma should be on pin 22 and chroma on pin 17. I'd try it but I don't have a display capable of doing S-video. Let me know if it works.

[gcl1984]

can I ask where you got this info.If this works it will be awesome.Much easier than my original plan ,which I still haven't gotten around to.

[davidleeroth]

I bought "a lot of original Sega documents and test equipment" from a guy. I don't know what that includes in detail (I haven't had a chance to pick it up yet). I asked him to look the 32X S-video pins for me and that's what he said.

More of what's included when I get my hands on it.

[Anthony1]

What if you're big TV(Samsung 61' DLP) also has VGA inputs? I've been kicking around the idea of picking up an XRGB2+ and hooking up my Genesis and other systems to it. But was thinking more along of lines of simply plugging them in via my TV's VGA port.

Would this look better, worse, or the same as using a VGA Wide Band componant adapter?



It would most likely look better through your VGA input. On my Princeton Graphics HDTV, which happens to have a VGA input as well, anything that has a VGA out that isn't an actual computer looks better on my wide band components. So for me, I'm going to need a VGA to component cable regardless. But for your DLP, you can probably just go VGA and it will look awesome.


It will be like you have a 61 inch RGB monitor. Because it takes the analog RGB signal, and converts it to 480p. Because the analog RGB signal is a much better signal to start with, the picture quality is "extremely close" to a native RGB signal.

It should at the very least be better than the S-Video signal.


I actually just bought a XRGB-2 that I will get later next week. As soon as I experiment with it, I'll report back.

[Kamino]

FREAKING RGB

[omnedon]

RGB rocks!

too bad i can'tuse it with the TV's in my home, or shop, or 99% of my customers sets...

[gcl1984]

So...

On the 315-5788 chip, luma should be on pin 22 and chroma on pin 17. I'd try it but I don't have a display capable of doing S-video. Let me know if it works.

If you look here www.segakore.net/articles/switch_32x.php
it shows pin 17 to be an input to select 50/60hz .

[davidleeroth]

So...

On the 315-5788 chip, luma should be on pin 22 and chroma on pin 17. I'd try it but I don't have a display capable of doing S-video. Let me know if it works.

If you look here www.segakore.net/articles/switch_32x.php
it shows pin 17 to be an input to select 50/60hz .

I think there's an error on pin numbering on the page. It should go like this:

1 - -32
. .
. .
16- -17

So the 50/60 pin is actually pin 32.
I've received the docs but I really haven't had a chance to read/scan them due to all this real life crap I've had to do recently. But some day, some time...

[gcl1984]

You are most definately right. Even when I was looking at the chip in the 32x I didn't realize that.I feel kinda stupid.
The world would be a better place if you looked through those docs.

[Kamino]

So...

On the 315-5788 chip, luma should be on pin 22 and chroma on pin 17. I'd try it but I don't have a display capable of doing S-video. Let me know if it works.

If you look here www.segakore.net/articles/switch_32x.php
it shows pin 17 to be an input to select 50/60hz .
What the blue hell is the point of 50/60 modding a 32x? I mean, if it'd actually let me play darxide, that'd be somethin'...but i mean, most 32x games are barely worth playing anyway, and i booted Alien soldier on a 32x with the genesis itself region modded...

[FABombjoy]

On the 315-5788 chip, luma should be on pin 22 and chroma on pin 17. I'd try it but I don't have a display capable of doing S-video. Let me know if it works.

Well, I don't know if anyone else has tried this yet, but I just did... and... nothing.

Well, not exactly nothing... I soldered a wire to 22 & hooked it to the luma in on my 1702. With brightness at full I can see a picture, but the signal is so low it won't sync. For kicks I tried the chroma as well but with the image so unstable & dim I can't tell if there is any color there.

I tried a few other points that 22 is connected to but it was the same story on each of them.

I tried with pin 22 both connected & disconnected to it's pad, same results either way. However, when disconnected the composite out is killed, so it must be somewhat important.

[davidleeroth]

Crap.

I'm gonna ask my friend to borrow his S-video projector for the weekend and try to sort it out. Hang in there.

[Kamino]

On the 315-5788 chip, luma should be on pin 22 and chroma on pin 17. I'd try it but I don't have a display capable of doing S-video. Let me know if it works.

Well, I don't know if anyone else has tried this yet, but I just did... and... nothing.

Well, not exactly nothing... I soldered a wire to 22 & hooked it to the luma in on my 1702. With brightness at full I can see a picture, but the signal is so low it won't sync. For kicks I tried the chroma as well but with the image so unstable & dim I can't tell if there is any color there.


I tried a few other points that 22 is connected to but it was the same story on each of them.

I tried with pin 22 both connected & disconnected to it's pad, same results either way. However, when disconnected the composite out is killed, so it must be somewhat important.


So, it needs to be amped then?

[gcl1984]

whats a 1702? :embarrassed:

[FABombjoy]

An amp would probably help.

1702 = Commodore 1702 monitor, a bench tester's best friend.

[Kamino]

An amp would probably help.

1702 = Commodore 1702 monitor, a bench tester's best friend.
and this is where i suck. heh.
Hrm, how do you guys figure out how to build those amps?
I admit i'm a hack job, i just do what the schematics tell me :P

1084 is my bench tester, heh.

[gcl1984]

why not just use the same amp that is used for the neogeo/genny?

[FABombjoy]

That circuit really isn't much of an amp, it's more of a buffer.

The Y/C signal outputs on the CXA1145 are at the correct levels, but they are insufficient to feed a monitor. It actually looks pretty good until there is a lot of brightness on the screen, then the picture destabilizes and goes to crap. Hence the need for buffering.

The pic coming off the 32x is so low it needs an amp (or something else).

[gcl1984]

Oh ok ,thanks for the clarification .
How bout this
http://i17.photobucket.com/albums/b82/neozeed84/hvc-101_video.gif

[FABombjoy]

Seriously, tho. The existing signal needs some analysis; just throwing random circuits at it is a sure-fire way to waste a lot of time. Might as well try the circuit featured in this movie (http://us.imdb.com/title/tt0089114/).

[davidleeroth]

I tried it but didn't see s**t. The projector has this auto circuit which chooses the input whenever there's signal feeded in but in this case it didn't trigger once. Either the signal was too low or it wasn't was it was expecting. I tried a few other pins too but it was all the same.

Here's the pinout for the chip, maybe you guys are handier with this stuff than I am.

http://www.students.tut.fi/~tiainen2/315-5788.jpg