The sega 32x, s-video modded

Here's how it looks:





Here's how I got to this point:

I recently decided to buy a mega everdrive since krikzz finally started making flash carts that use ram chips therefore the thing will basically last forever. Since the mega everdrive can play 32x roms I bought myself a cheap 32x from ebay (something like 35$ shipped). I didn't get any cables so I was planning on just wiring the system up myself. I asked tiido a lot of questions about what's needed to get it running and it's pretty simple.

After cracking the system open and doing my best to understand the hardware I wired up everything by rgb and externally encoded the outputted rgb to s-video. The picture wasn't bad but it wasn't as good looking as I wanted it to be. I know from experience that re-encoding the rgb over and over will decrease the quality so I decided to see if it's possible to s-video mod a 32x. I found this helpful thread here:

http://www.sega-16.com/forum/showthread.php?16590-32X-S-Video-Mod

Pretty cool thread and it pointed me to where to tap s-video from the system. This thread also mentioned that you need an amp on luma to get a signal. I had a spare luma amp sitting around that I built years ago for the s-video mod on the cxa1145 that's built into my genesis. Here's the amp, just one transistor and I put a custom strength resistor to get the brightness just perfect:

http://www.jamma-nation-x.com/jammax/genesismods.html

I can't even remember what strength resistance I'm using I built that thing so long ago. Anyway wiring up this amp made it work so now I had s-video coming from the 32x. The chroma line didn't need any parts I could just straight wire it. However something was causing the luma to be blurry, like composite quality blurry. After talking to tiido and experimenting a bit I managed to fix the blur. Here's a before and after screenshot:





yeah uhh....night and day. For the sake of comparison here's screenshots of the s-video from a cxa1145 and from a cxa2075 circuit.





These are of course from my capture card that picks up EVERYTHING. For some reason when my cxa2075 circuit is plugged into the system the image flickers....even when I'm getting rgb from the cxa1145. As soon as I unplug my cxa2075 circuit the flickering goes away...oh well.

On my tv however the 32x'ified picture looks perfect. The jailbars are 100% gone, and what's left of the rainbow banding is just as strong as it was from my cxa2075 circuit (so weak it's not annoying at all). Also the colours look better for some strange reason. Therefore I like how it looks on my tv more than the image from my cxa2075 circuit. Also to weaken jaiblars on my cxa2075 circuit I had to branch off a long s-video cable to ghetto filter them and it was annoying. With the 32x I don't need to do any tricks it's just jailbar free....and it plays 32x games!

Here's some pictures of my rig







Why buy expensive cables when I can build one out of old IDE cables

....now to get my everdrive so I can play 32x games....

My schematic



I only just now realized that the colour line is being tapped after it goes through its circuit? Whatever I think the colour looks great so I'm not going to mess with it.

Here's the idiot proof step-by-step instructions I posted on sega16 from a request:



step 1: find the 315-5788 chip.

step 2: find pin 22 of this chip. If you're ever uncertain whether you have the right pin or not just look at the circuit that the pin is connected to it should be the same as the shematic in my picture.

step 3: desolder the small zero ohm surface mount resistor that pin 22 is connected to. I pointed an arrow to where the 0 ohm resistor used to be in my schematic. This will be the first surface mount part that pin 22 connects to on the pcb exactly how it's shown on the schematic.

step 4: solder a wire that connects to pin 22, be certain that pin 22 is connected only to your wire and nothing else. In step 3 we disconnected pin 22 from the filter circuit by removing that resistor. Disconnecting the filter circuit gets rid blur effect on the s-video picture. If the filter is disconnected then you'll have nice crisp and sharp s-video.

step 5: solder the other end of your wire to a 1 resistor luma amp / buffer / whatever you want to call it. Here's the amp I used:

http://www.jamma-nation-x.com/jammax/genesismods.html

If you need to know where to get +5v from the 32x just lookup the pinout of the av port and you'll see there's a +5v pin right on the connector that you can use. Here's a picture of the av connector pinout:



step 6: solder another wire to pin 19 of this chip, this wire will be your chroma line. I don't recommend soldering these wires directly onto the chip pins as the pins are tiny and very easy to bridge. I just soldered my wires onto the first surface mount component that the traces from the pins are connected to. In the case of the luma line (pin 22) I just soldered my wire to the exposed trace end of where the 0 ohm resistor used to be soldered to.

step 7: wire the outputs of the luma amp and the chroma wire into a s-video connector. Assuming you didn't mess up the mod you should have nice looking s-video. Don't forget to wire up ground otherwise you'll get either no picture or something insanely horrible looking.

step 8: Change the strength of the resistor on your luma amp until the brightness looks perfect on your tv.

step 9: play and enjoy.

Where you install your s-video connection is up to you. I decided to desolder the av output port and glue my s-video head where the output port used to be:



A s-video jack is almost exactly the same size of the sega genesis 2 av port so it's a perfect fit. I figured this's nicer looking than cutting an extra hole in the 32x case somewhere.

Cool I have to try this myself one day. The 32X unit is cheap nowadays...

Maybe offtopic, but what games do you recommend on the 32X?

ProD1gy84 wrote:

Cool I have to try this myself one day. The 32X unit is cheap nowadays...

Maybe offtopic, but what games do you recommend on the 32X?

I have no clue I don't have any 32x games yet. I'm still waiting for my mega everdrive to show up so I can try them. I've been playing my 32x system with genesis games and the s-video looks absolutely perfect with every game.

Some proof that there's zero video interference from the s-video coming out of my modded 32x:





These pictures don't do it justice at all but it's the best I could manage with my not so great digital camera.

I ran a couple of screenshots through a filter that makes it look the same as on my tv





It's a bit sharper on the tv but you get the idea.

So you're saying in effect that one is better off playing normal Genesis games via the 32X as it provides better quality video?

bacteria wrote:

So you're saying in effect that one is better off playing normal Genesis games via the 32X as it provides better quality video?

Absolutely! All the video signals coming out of the genesis (rgb, composite, s-video when modified) suffer the same video issues. The cxa1145 encoder suffers semi weak colours, vertical bars in the image, and rainbow banding. The vertical bars and rainbow banding actually come right out of the vdp chip itself so they're impossible to eliminate at best you can attempt to build a hardware filter. The 32x makes the colours nice and vibrant, gets rid of the vertical bars 100%, and makes the rainbow banding so weak it's not an issue. Basically the 32x cleans up the image and makes it look perfect, the 32x acts as a hardware filter. Even my best setup with the stand-alone genesis didn't quite measure up to the s-video image that comes out of the 32x only because I wasn't able to 100% get rid of the jaiblars with my circuits.

The first official playthrough recorded from the s-video of my 32x:



If that isn't perfect looking I don't know what is.

Im impressed how sharp it looks. But is your capture card making it brighter than normal? To me it looks too bright...

ProD1gy84 wrote:

Im impressed how sharp it looks. But is your capture card making it brighter than normal? To me it looks too bright...

Yes it's my 12$ capture card, it looks perfect on my tv.

Some 32x eye candy:

Ah, I think I need a 32x, the jailbars on streets of rage 1 are really prominent I was playing it last night. The picture looks incredible, hmm I also noticed it seems to run much smoother, does the game just slow down on multiplayer? I've never played it single player. I have a model 1 genesis.

glenn101 wrote:

Ah, I think I need a 32x, the jailbars on streets of rage 1 are really prominent I was playing it last night. The picture looks incredible, hmm I also noticed it seems to run much smoother, does the game just slow down on multiplayer? I've never played it single player. I have a model 1 genesis.

I've never played sor1 in multiplayer. Honestly I've only played it 7-8 times. But where you live don't you have rgb? If you're getting jailbars in rgb I do have a fix. But just a warning the fix will disable colour in s-video, composite, and rf:

https://16bitgamer.canadian-forum.com/t141-sega-genesis-32x-and-component-video

Revised circuit diagram:

Hi Drakon,
I just want to verify what I think I see in your diagram.

1. Find the video chip in the 32x.
2. Desolder the resistor that connects to pin 22 on said chip.
3. Solder pin 22 to pin B on the transistor.
4. Solder pin C on the transistor to a 5v source.
5. Solder pin E on the transistor to a 50ohm resistor.
6. Solder said 50ohm resistor to Luma pin on the S-Video socket.
7. Solder Chrom Pin on S-Video socket to pin 19 on the video chip.
8. Ground the S-Video Socket.

Is that really everything that needs to be done, or am I missing something? If that's it my weekend just got a little busier!

Yup.

zypherion wrote:

Hi Drakon,
I just want to verify what I think I see in your diagram.

1. Find the video chip in the 32x.
2. Desolder the resistor that connects to pin 22 on said chip.
3. Solder pin 22 to pin B on the transistor.
4. Solder pin C on the transistor to a 5v source.
5. Solder pin E on the transistor to a 50ohm resistor.
6. Solder said 50ohm resistor to Luma pin on the S-Video socket.
7. Solder Chrom Pin on S-Video socket to pin 19 on the video chip.
8. Ground the S-Video Socket.

Is that really everything that needs to be done, or am I missing something? If that's it my weekend just got a little busier!

Sick, thanks.

Oh, last question, I assume you pulling composite audio directly from the genesis, yes?

zypherion wrote:

Oh, last question, I assume you pulling composite audio directly from the genesis, yes?

Not sure what "composite audio" is but yes I'm pulling audio from the genesis. I was very curious how the 32x works when I first picked one up. The 32x mixes in audio through the cartridge connector so anywhere you get audio on the genesis will have the 32x audio mixed in whether it's the headphone jack or the av port on the back. The way the 32x adds video is it takes the rgb + sync output from the genesis and then overlays its own graphics over the existing image. Next the 32x video encoder converts the graphics into s-video, then has external circuits for the s-video which changes the signal qualities and refeeds the signals back into the chip for them to be combined into composite video which is output on another pin. The 32x video encoder chip also outputs the 32x + genesis image combination over rgb. For some reason like a lot of old consoles s-video is right there in the system but it wasn't wired up. It seems a lot of companies out there went with the all or nothing approach, all being rgb, nothing being composite or even rf. Proper s-video is barely a downgrage from rgb, in fact it's extremely hard to see the difference if the s-video is done right. Since a lot of tvs in the western world have s-video it's great to wire it up, especially considering a lot of older consoles generate s-video already.

Reviving this project with some questions.

I just finished this mod, which looks great, I can now actually read all the words on my rpg games. I noticed very slight jailbars though, which I really only see when standing close to the TV, so its only a minor complaint. I used the same schematic you gave, except I used a 46 ohm resistor instead of 50 (only had 46 ohms around the house). I found this project in another forum where you mentioned that the 2n3904 could cause some jailbars. I was wondering if you had found a way to reduce or eliminate them with a different transistor? If not, again, its only a minor complaint.

joofcorn wrote:

Reviving this project with some questions.

I just finished this mod, which looks great, I can now actually read all the words on my rpg games. I noticed very slight jailbars though, which I really only see when standing close to the TV, so its only a minor complaint. I used the same schematic you gave, except I used a 46 ohm resistor instead of 50 (only had 46 ohms around the house). I found this project in another forum where you mentioned that the 2n3904 could cause some jailbars. I was wondering if you had found a way to reduce or eliminate them with a different transistor? If not, again, its only a minor complaint.

Are you sure you're posting in the right thread? The 32x s-video mod is jailbar free. The only time I got jailbars from the 32x is when I added a transistor amp to the chroma line, in my schematic I onjly have it wired up to luma.



It's jailbar free, just a little rainbow banding that mostly doesn't show up on a tv: