NES S-Video Mod

I’ll admit, when I was young I wasn’t a big fan of the Nintendo Entertainment System (a.k.a. NES). I think because I grew up with the Sega Genesis, the NES seemed inferior to me at the time, probably due to graphics. Oh young naive me, if only you knew what I know now. What I know now, is that the NES is the console that single handedly saved video games from the crash in the 80’s, solidified Nintendo as the leader in gaming (at the time), used the first “modern” controller, and launched some of the greatest franchises in gaming. The only thing lackluster about the NES is the dull color palette and fuzzy composite video. But can that be improved? I started researching ways to improve the NES video quality by giving it s-video, and I finally succeeded!


My NES; a system I didn't appreciate as a kid, is now one of my favorite systems on my collection.
My NES; a system I didn’t appreciate as a kid, is now one of my favorite systems in my collection.


The original method to improving the video and color quality on NES systems was to pull the video encoder from a Nintendo arcade machine called a Playchoice 10 and then use it in the NES. The arcades were built similar to NES consoles, but had newer hardware which included better video output. However, as this mod started to become more popular, it was getting harder to find Playchoice 10 arcades to pull apart. Not to mention, the idea of gutting a perfectly fine Playchoice 10 for it’s video chip sounds sad and cruel to a hardware guy like me.


The Nintendo Playchoice 10 Arcade Cabinet. Many lost their lives to hardware modders.
The Nintendo Playchoice 10 Arcade Cabinet. Many lost their lives in the quest to find better video quality for the NES.


For a long time, I thought I would just have to leave my NES on composite video, which was better than  RF, but definitely not ideal. Until I finally discovered a kit that supposedly allowed NES and Famicom consoles to output S-Video and RGB. Here is the kit I discovered:

And here are the instructions for installing the kit:

After studying the instructions, and obsessing over whether or not I had to skills to do this mod, I finally decided to take the plunge and I ordered a kit for my NES “front loader” console.


The NES kit Board; the key part of the kit.


Here is the basic principle behind the kit as I understand it. The NES has a chip on the board called the PPU (Picture Processing Unit) that takes the image rendered by the NES and it converts it into a signal that can be recognized by a TV. The NES’s PPU can only output RF (yuck) and composite. This is a problem, because there is no way to easily mod a better connection in there.

For example, I wrote articles about modding s-video to a Sega Master System and a Sega 32x, and I’ve done the same thing to a Sega Genesis. This was fairly easy because the PPUs of those systems supported s-video, but it was never actually used in the system. That means, all I had to do was tap into those dormant s-video connections to get s-video. Thanks Sega! Also, the Playchoice 10 arcade has a PPU that supports RGB that is compatible with the NES, which is why it is highly sought after. It allows there to be a connection for modders to tap in to.

But for a stock NES, there’s nothing to tap in to, which is what this kit fixes. That board sits between the NES and the PPU and intercepts the picture going to the PPU. It can then output RGB or s-video AND it can improve the NES’s rather drab color palette!

However, the instructions were… ok, but not great. Hopefully this post will help anyone who is thinking about attempting this mod.


Step 1: Remove the PPU

Unfortunately, step one is the most difficult step. I had to remove the PPU chip while making sure not to damage it because it will be needed later. The official instructions said it takes most people 30 minutes to 2 hours. Ha! This step alone took me nearly 4 hours! I’m not a pro at soldering (or de-soldering in this case) but I managed to remove the PPU with a soldering iron, and a basic Radio Shack solder sucker.

Removing the 6 screws on the bottom allowed me to take the top cover off. The NES doesn’t have the tri-wing screws that later Nintendo systems have (thank goodness)!


NES without it’s top cover


Removing a few more screws lets me take the shield off.


You can now see the (notorious) cartridge slot on top.
You can now see the (notorious) cartridge slot on top.


After removing the screws going through the cartridge slot, the whole board can be removed. There are 3 cables attached to the board that need to be detached before the board comes out.


NES board
The board separated from the NES case.


The cartridge slot can be removed from the main board now. It’s tight, but it should just pull off.


NES Board
NES board fully separated from the other bits.


Most of the important stuff is on the bottom of the board. That’s why the board must be completely removed. On the bottom of the board, there are 2 big chips. One chip is the CPU, the other is the PPU. The PPU may have a different part number on top depending on which region the NES is from (NTSC, PAL, etc…)


This big chip is the one that needs to be removed. This is the hardest part.


I started by adding more solder to the back of the board on each of the 40 pins. I did this so that (hopefully) the solder sucker will work better if there is a bit more solder.


Back of where the PPU is


After I’ve removed solder from some of the pins.


There were about 3 pins that were rather difficult. The official instructions noted that these pins were connected to a copper ground plate. This made it hard to get the pins hot enough to remove the solder. I found that holding the board up to a light allowed me to see which pins contacted the board.


NES Board
On the PPU (the large chip on the right) you can see where the ground pins on the board contact the copper on the bottom of the chip.


After using the solder sucker on all the pins, I made sure that each pin seemed free to move. However the chip was still firmly attached. I tugged the chip while heating the individual pins hoping the chip would work loose. I did this for about 2 hours, then quit for the time being until I could think of a better way to remove this chip.

The next day I had the idea of creating a rig out of paper towel rolls, ribbon, and a paint stick to keep constant pressure on the chip while I heat the pins with a soldering iron.  Unfortunately, it didn’t really work.


NES mod
It sounded like a good idea in my head


I had been working on removing this PPU for nearly 3 hours total now. At this point, I was thinking about taking this to some sort of professional that might be able to remove it for me. But then I got to thinking… Each pin seemed like it was free, so I took a risk and just pulled rather hard on the PPU wondering if I just needed more force than I was giving it. Suddenly, half of the pins came up! Then I knew it would be much easier to remove with only one side to deal with!


Halfway removed!


After working on the other side, I finally heard a pop, and the PPU pulled free! But after working on this for so long, I was worried that the PPU (or mainboard) might be damaged from the pulling and heating from the soldering iron.


The most beautiful sight I have ever seen


NES Board
Where the PPU was


Step 2: Solder the PPU and mounting pins


I then soldered the pins that came with the kit to the NES board. The go where the PPU was, and allow the kit’s board to be mounted to the NES board.


NES S-Video Mod
The pins that will attach to the kit board


NES S-Video Mod
The pins are about to be soldered to the NES board.


I then soldered a socket to the kit’s board. This is what will go on the pins that I just finished soldering to the NES’s board.


NES S-Video Mod
The socket that allows the kit’s board to be mounted to the pins on the NES’s board


NES S-Video Mod
The other side of the board


I then had to solder the PPU to the kit board. This was a bit worrying, as I knew that if I made a mistake, I would have to desolder the PPU again, which I did NOT want to go through!


NES S-Video Mod
The NES PPU soldered to the kit’s board


Step 3: Move the stuff that’s in the way of the board.

So there’s a problem with mounting the kit board flat against the NES board. There are 2 capacitors that are in the way and preventing the board from sitting on the pins. To fix this, I had to heat up the legs of the capacitors with a soldering iron, and pull them out enough to push them flat.


NES S-Video Mod
The 2 capacitors (blue cylinders) are in the way


NES S-Video Mod
After I flattened the 2 capacitors


NES S-Video Mod
Testing to make sure the board fits. Success!


Step 4: Solder the correct jumper

This was a step that I read in the instructions, but couldn’t figure out what I was supposed to do. I was supposed to solder a jumper depending on the NES’s region (in this case, North America), so I was supposed to solder the J5 jumper. It took me a long time to figure out where that was, but I finally found it. I marked it in the picture below. If your NES is not an NTSC (North America) model, then you’ll need to find a different jumper.


NES S-Video Mod
That little pad marked J5 is what needed to be soldered.


 Step 5: Wiring

The wiring guide can be found with the official instructions. It seemed complicated, but it wasn’t too bad when it was taken one part at a time.

I started with the power system. The new board apparently causes the NES’s voltage regulator to run too hot, so a second voltage regulator was included with the kit that helps take the power load off the NES. This regulator is soldered to the voltage regulator on the NES, and then it is soldered to the kit board.


NES S-Video Mod
The kit’s board and voltage regulator chip


NES S-Video Mod
Voltage regulator connected to the board


I then soldered the cables that will go to the S-Video jack. There are 3 cables, including chroma (color), luma (brightness), and ground.


NES S-Video Mod
Added video cables that will go to the S-Video jack


Part of this mod includes a switch that switches the colors between the NES’s original colors, and an improved color palette. I went ahead and soldered these wires on the board.


NES S-Video Mod
After adding the palette switch wires


The mod also needs an audio signal. To do this, the board has to be connected directly to the NES’s CPU. The CPU looks almost exactly like the PPU. There are 2 pins that need to have wires soldered to.




NES S-Video Mod
Here are the 2 pins I soldered the 2 wires to on the other side of the board.


Since I was almost ready to mount the kit board to the NES mainboard, I went ahead and soldered the kit voltage regulator to the NES’s regulator.


NES S-Video Mod
The kit regulator soldered to the NES’s voltage regulator.


This is the point I realized I made a mistake. If you look at the pictures above the wires were all facing away from the board. When I tried to mount it, the wires were in the way of the cartridge slot, so I had to re-solder most of them to make the face the other direction. After that, it fit like a glove!

I also soldered the wires that went to the audio on the CPU.


NES S-Video Mod
Kit board mounted to the NES’s mainboard.


NES S-Video Mod
This is the part that little voice in my head was saying “there’s no way this is going to work.”


Step 6: Drilling the holes and connecting the jacks

Before I put the board back in to the case, I had to drill holes for the palette switch, the audio jack (which was included in the kit), and the s-video jack (also included). The good news is, the NES is full of empty space, especially in the back. So finding a place to put the jacks, wasn’t hard.


NES S-Video Mod
Holes drilled with the switch and the S-Video port already installed.


At this point, I realized I may have made a mistake with the s-video jack. The screw post behind the jack means it’s going to be really hard to solder the pins on that board. You can’t really tell from the picture, but I only have a gap about the size of a penny, and it’s going to be tough to get to those pins.


NES S-Video Mod
I’ve made a terrible mistake…


NES S-Video Mod
The s-video and palette switch from the back side.


I then soldered the palette switch and the s-video jack.

For the audio I had 2 wires (audio 1 and audio 2), however the NES wasn’t designed for stereo sound. Because of this, there can be some strange, and even annoying audio splitting going on if one audio signal is connected to left and the other connected to the right. So I decided to connect the 2 audio signals together. This means both left and right speakers will be getting audio, it will just be the same sounds. It’s one step up from mono, but still better than the NES’s one audio plug.


NES S-Video Mod
The audio and s-video jacks wired up

Step 7: Stick the voltage regulator somewhere, and reassemble the NES

Even with all the extra stuff, I managed to get the board back in the case.


NES S-Video Mod
My train of thought at this point: “good lord what have I done to this poor NES???”


I forgot to get a picture, but the voltage regulator needed to be mounted in a way that it wouldn’t touch anything. I got a hot glue gun, and stuck it to the back of the case next to the audio jack. I also hot glued the wires connected to the palette switch and the s-video jack. I just taped everything else down with electrical tape.

Then I reassembled the whole monstrosity piece of art.


NES S-Video Mod


NES S-Video Mod
The back with the new ports and palette switch


 Step 7: Troubleshooting (whoops)

So I go plug it in, connect the audio, connect s-video, and turn it on. It powered up, but had the flashing grey screen of death (it IS an NES afterall). After re-inserting the cartridge I got a very garbled version of the game. I could tell the picture was very clear, but the game was completely scrambled.

Of course, I thought it was just the cartridge connection, so I took the NES apart, cleaned the cartridge connections, and put it back together. Same problem.

At this point, I noticed something. When the game glitched up, it always did so the same way. If it were a cartridge issue, it would probably be random. So out of curiosity, I plugged in a controller and discovered the game was playable! Here’s what Super Mario Bros. 2 looked like:


Super Mario Bros 2
Good ol’ Super Mario Bros. 2, just like I remember it.


When searching Google for the problem, I only found one instance of someone having this issue. It sounded like the game was working, but the PPU was pulling the wrong sprite data. This made sense, because the game was playable, but the sprites were all wrong. At this point, I was really hoping I didn’t fry the PPU or cut a lead somewhere.

I decided to go back and add some solder to all the pins on the PPU. So I disassembled the whole thing and pulled out the kit board. I saw a couple pins that didn’t have much solder on them, so I redid them all. I reassembled everything, and then:


Super Mario Bros 2 s-video
Success! It’s the most beautiful sight I’ve ever seen since I’ve been able to remove the PPU.


It worked! It must have been a pin on the PPU that wasn’t full connected. The image was very sharp and the colors were bright. The only problem is, there was a wavy interference pattern moving up the screen. You can see it in the picture above. Now that the picture was so clear, it was really quite annoying. The AC adapter that came with my NES was a third party replacement, so I ordered an original power supply from eBay. The better power supply made a world of difference!


Mega Man 2 NES
The original AC adapter fixed all interference issues.


 Before and After

Here are some comparison pictures I took of the NES connected to an HDTV.

Super Mario Bros 3 Composite
Before. Notice how dull the red on Mario is.


Super Mario Bros 3 s-video
After. You can see how much brighter the red is on Mario and the clouds.


Mega Man 2 Composite
Before. Note Mega Man’s lumpy feet.


Mega Man 2 s-video
After. Notice how you can clearly see each pixel.


Also, I connected the system to my CRT TV and tested the Zapper. It worked great!


Duck Hunt
That dog’s grin has never looked so sharp!



This was by far the toughest (and most expensive) mod I’ve done, but I’m glad I did it and that it worked out in the end! Now that I’m a big fan of the NES, I’m glad that it can go in the Museum on the shelf with the rest of the s-video modded consoles.

After all, no game console collection is complete with out the console that started a revolution!


    1. I’m glad you liked it! This was easily the toughest mod I’ve done. I barely trusted myself to work on my own NES, let alone someone else’s, lol.

  1. Thank you very much for this! I will use this for my kit coming soon as this is the exact setup I will be using.

  2. Great write-up, and excellent pictures! I did have a question before I jump in and take the plunge with my childhood NES, what gauge wire did you use throughout your mod? and did you do any extra insulation or anything to protect the s-video wires from interference between the jack and where they attach to the kit board?

    1. I’m glad you like it!

      I used some lighting wire that came as a flat group of four (one red, blue, green, black). I’m not sure what gage it is, but it’s probably a bit too big to be honest. And I didn’t do any extra insulation. I tried to keep the wires fairly short, but overall there’s not much room for thicker wires in there.

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