Genesis:S-Video Mod

The Sega Genesis doesn't support native S-Video through its A/V output, but it is possible to mod most Sega Genesis consoles to output S-Video with just a few components and an S-Video jack. The mod somewhat differs depending on the video encoder inside of your console, but both are relatively easy and can be done by a careful beginner to soldering. Genesis consoles with a Samsung KA2195D video encoder cannot be modded for S-Video, as they lack the necessary Chroma and Luma lines to do so. Most Model 1s will have a CXA1145, but some later ones can have the Fujitsu MB3514. Model 2s are even more scattered as they can possibly have any of the four encoders. The only way to be sure which encoder you have is to open up your console. All known Model 3 Genesis consoles contain the CXA1645.

Required Materials and Tools

• JIS/Philips Head Screwdriver
• Soldering Iron
• Leaded Solder
• Kapton Tape
• Heat Shrink Tubing
• 28 AWG Wire
• S-Video Female Jack

Flux isn't necessarily required but it may help. You can get the S-Video Jack as a panel mount or a long socket variant from Console5. A panel mount jack would be perfect if you plan on drilling out a part of your console's shell to put in a neat-looking flush connector. The long socket may be perfect for you if you don't want to modify your console's shell, as you can dangle it out of an unused hole on the back of every Model 1 and Model 2 Genesis.

Other parts will differ depending on what video encoder you have:

Sony CXA1145 Installs

• 1x 220uF 6.3v Capacitor
• 1x C945 Transistor
• 1x 75 Ohm 1/4 Watt Resistor
• 1x 33 Ohm 1/4 Watt Resistor

This can be purchased as a kit from Console5.

Sony CXA1645/Fujitsu MB3514 Installs

• 2x 220uF 6.3v Capacitors
• 2x 75 Ohm 1/4 Watt Resistors

This can be purchased as a kit from Console5.

Installation for CXA1145

• 

  Diagram for the CXA1145

• 

  Back of the S-Video Jack

1. Make sure your console is unplugged first, and then start by opening up your console and removing the top metal shield inside.
2. Solder two wires to the CXA1145 encoder, with one wire being on pin 15 and the other being on pin 16. Color coded wires may help but aren't required. You may want to add a small amount of solder to the wire and/or the pin before joining them. Flux may help with this as well.
3. Find a suitable area to place the capacitor, resistors, and transistor. One method of this is putting a layer of some kapton tape over an area of the board with a decent amount of empty space to place these components. Make an approximation of where you think the components are best placed in your console and trim the legs on the components so they won't touch the board. You may need to use multiple strips of kapton tape side-by-side to make a decent insulating space for your components.
4. Solder the other end of the pin 15 wire to the positive leg of the 220uF 6.3v capacitor. Then solder the 75 Ohm resistor directly to the negative leg of that capacitor.
5. Solder the other end of the pin 16 wire to the middle pin of the C945 transistor. You can optionally bend the legs of the C945 outward to be a bit safer with the connections. Solder a wire from the right pin of the C945 transistor to a source of +5V on the Genesis main board, such as from Pin 12 of the CXA1145. Solder the 33 Ohm resistor directly to the left leg of the C945 transistor.
6. For no drill/cut mods, you may want to start putting the outer shell of the S-Video socket over the wires of the next few steps before soldering both ends as you will not be able to put it on afterwards. For drill/cut mods, you may want to unscrew the mounting nut from the front of the S-Video panel mount jack and get it over all of your wires before soldering the other ends as you will need to screw it into the back of the jack to mount it to the console.
7. Solder a wire from the other leg of the 75 Ohm resistor and put a heat shrink tube over it before soldering the other end of the wire to the Chroma pin of the S-Video jack.
8. Solder a wire from the other leg of the 33 Ohm resistor and put a heat shrink tube over it before soldering the other end of the wire to the Luma pin of the S-Video jack.
9. Solder a wire to each of the S-Video jack's ground pins and put heat shrink tubes over them before soldering the other ends of these wires to the negative leg of a 47uF 16v capacitor back on the main board. Both wires can go to the same capacitor's negative lead.
10. You have made all the necessary connections. Now you should put stick the components from the mod down with some kapton tape, over the other kapton tape insulating layer you put on the board earlier. Make sure none of the leads from the separate connections are touching each other. Use multiple layers of kapton tape on each connection set if needed.
11. Before encasing/mounting the S-Video jack, at this point you can test if the mod works. If it worked, turn off and unplug the console and move on to the next step. If it doesn't work, double check that you have the correct polarity on the capacitor and that the wires are going to the right pins on the C945 transistor and the S-Video connector.
12. Bring the heat shrink tubes all the way to the S-Video jack's pins where the wires are soldered in and heat the tubes with something like a lighter or a hair dryer.
13. For no drill/cut mods, put the two halves of the inner casing of the S-Video jack together and slide it into the outer shell of the socket. For drill/cut mods, mount the S-Video jack in your cut-out by screwing the mounting nut from the back side of the connector. Make sure you orient the S-Video jack upright before fully mounting.
14. Reassemble the console including the metal shielding. You're done!

Installation for CXA1645/MB3514

• 

  Diagram for the CXA1645/MB3514

• 

  Back of the S-Video Jack

1. Make sure your console is unplugged first, and then start by opening up your console and removing the top metal shield inside.
2. Solder two wires to the CXA1645/MB3514 encoder, with one wire being on pin 15 and the other being on pin 16. Color coded wires may help but aren't required. You may want to add a small amount of solder to the wire and/or the pin before joining them. Flux may help with this as well.
3. Find a suitable area to place the capacitors and resistors. One method of this is putting a layer of some kapton tape over an area of the board with a decent amount of empty space to place these components. Make an approximation of where you think the components are best placed in your console and trim the legs on the components so they won't touch the board. You may need to use multiple strips of kapton tape side-by-side to make a decent insulating space for your components.
4. Solder the other end of the pin 15 wire to a 75 Ohm resistor. Resistors don't have polarity so you don't have to worry which side of it you solder to. Then solder the positive end of a 220uF 6.3v capacitor directly to the other leg of the resistor.
5. Solder the other end of the pin 16 wire to the other 75 Ohm resistor. Then solder the positive end of the other 220uF 6.3v capacitor directly to the other leg of this resistor.
6. For no drill/cut mods, you may want to start putting the outer shell of the S-Video socket over the wires of the next few steps before soldering both ends as you will not be able to put it on afterwards. For drill/cut mods, you may want to unscrew the mounting nut from the front of the S-Video panel mount jack and get it over all of your wires before soldering the other ends as you will need to screw it into the back of the jack to mount it to the console.
7. Solder a wire from the negative leg of the pin 15 capacitor and put a heat shrink tube over it before soldering the other end of this wire to the Chroma pin of the S-Video jack. If you are not drilling your console, you may want to have enough length to route this through the unused hole on the back of the console. The S-Video socket variant is a little deep so make sure you have a bit of extra wire. Remember that the wires for this mod may also have to go around the console's metal shielding when it goes back together so loosely put the shield on to test fit your wire route.
8. Solder a wire from the negative leg of the pin 16 capacitor and put a heat shrink tube over it before soldering the other end of this wire to the Luma pin of the S-Video jack. Again, mind the length of the wire for where you want it to go.
9. Solder a wire to each of the S-Video jack's ground pins and put heat shrink tubes over them before soldering the other ends of these wires to the negative leg of a 47uF 16v capacitor back on the main board. Both wires can go to the same capacitor's negative lead.
10. You have made all the necessary connections. Now you should put stick the components from the mod down with some kapton tape, over the other kapton tape insulating layer you put on the board earlier. Make sure none of the leads from the separate connections are touching each other. Use multiple layers of kapton tape on each connection set if needed.
11. Before encasing/mounting the S-Video jack, at this point you can test if the mod works. If it worked, turn off and unplug the console and move on to the next step. If it doesn't work, double check that you have the correct polarity on the capacitors and that the wires are going to the right pins on the S-Video connector.
12. Bring the heat shrink tubes all the way to the S-Video jack's pins where the wires are soldered in and heat the tubes with something like a lighter or a hair dryer.
13. For no drill/cut mods, put the two halves of the inner casing of the S-Video jack together and slide it into the outer shell of the socket. For drill/cut mods, mount the S-Video jack in your cut-out by screwing the mounting nut from the back side of the connector. Make sure you orient the S-Video jack upright before fully mounting.
14. Reassemble the console including the metal shielding. You're done!