Sega 32X S-Video Mod (V2)

Sega 32X

My 32X started working having issues the other day, and upon opening up to inspect it, 3 out of the 4 S-Video mod wires broke. It was one of the first mods I did, and I wasn’t as good at soldering as I am now. I tried reassembling it using the guide from my 32X S-Video post, but I realized my post had some incorrect information! This won’t do, so here’s my revised article.

First of all, I highly recommend checking out RetroTimeGames 32X S-Video mod. They have some great information and pictures on how to do this mod. I’m hoping my steps will help compliment his information.

So let me explain what we’ll be doing, and the diagram below to help with this. S-Video is simply a Luma (brightness) and Chroma (color) connection with a couple of ground connections. The 32X chip actually puts out Luma and Chroma, but it gets combined into ugly composite. We’ll be tapping into the Luma and Chroma signals to create an S-Video connection. Chroma can come straight off of the chip at pin #3 as shown below. The 2 grounds can also be easily grounded to the 32X. Luma is where it gets a little bit complicated.

The 32X video encoder doesn’t put out a strong enough Luma signal to go straight to S-Video, so we’ll have to use a transistor to amplify the signal. A transistor uses 3 legs, a collector (which takes power from a source, a base (which takes the signal), and an emitter (where the amplified signal goes). We’ll connect the collector to a capacitor already on the 32X where it will get it’s power from. Then the base will connect directly to the Luma signal on the video encoder. Then the emitter will go to a resistor, and then straight to the Luma connection on the S-Video port.

32X S-Video Mod

Sega 32X
Here’s the main board of the 32X. The 2 large white ribbons go to the CPUs, (Protip: reseating the white cables will fix most 32X problems)! The spot we will be working on is the rectangular black chip to the left in the picture.

 

The very first thing we need to do after opening the 32X is remove a small surface mounted resistor. The resistor is right next to the video encoder chip and is labeled as R45. You can see it in the picture below. The best way to remove it, is to put a bit of solder on your iron, and heat up one side until it starts to move. Then use tweezers to pull it completely off. In later pictures you can see what it looks like with R45 removed.

 

Sega 32X S-Video
Here’s a closeup of the video encoder chip. You can see where the R45 is pointing to the resistor that we need to remove.

 

Seva 32X S-Video
I cut the wires and formed this sort of shape with the transistor and the resistor. I also put some solder on the ends, which will make things much easier.

 

Sega 32X S-Video
The leg opposite of the resistor was soldered to the + side of the capacitor, which is opposite the stripe. The middle leg went to the point the R45 used to be (the point closest to the chip right across from pin 6). And the leg with the resistor was pointed up, to get it out of the way. Ignore the wire connected to the resistor in this picture.

 

Sega 32X S-Video
Here’s another angle that shows how one leg of the transistor goes to the capacitor, one goes to where the R45 resistor used to be, and the other goes to the resistor which is pointed up.

 

Sega 32X S-Video
Now we install the port on the top shell, and drill a hole for the S-Video jack. I chose the left side (when viewing from the back) as there is a gap in the metal shielding at that point which will help everything fit without cutting the shield. Once you have installed it and you know the connections are ok, go ahead and hot glue it together. This will help later on when soldering the wires to the 32X.

 

S-Video
Pin 1 and 2 on an S-Video connection are both ground. You can wire these both to the same ground while leaving 2 long wires for 4 and 3.

 

Sega 32X S-Video
I wired the 2 grounds to the shield. I just scratched the surface with a knife so that the solder and wires would stick.

 

Sega 32X S-Video
Then you wire the Chroma pin to the resistor. The Luma wire will be wired straight to pin 3 on the chip which is right between the corner of the chip (pin 1) and where we soldered the transistor (pin 6). You can also solder the wire to the resistor across from pin 3, which is the one that has C77 written next to it.

 

Sega 32X S-Video Mod
At this point test it and make sure it works. If you’re good to go, carefully apply hot glue to the area you worked on. This will help keep the wires from being pulled from the chip.
IMG_20131001_173351553
You don’t need to completely reassemble it to test it. Just be careful, and make sure the ground wire is connected to the metal shield, otherwise you may not get an image.

 

IMAG0091_BURST008
And that’s it! Enjoy the best quality (non RGB) video you can get from a Genesis!!!

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