In 1993, Nintendo released new and improved revisions of both the Nintendo Entertainment System in North America and the Nintendo Famicom in Japan. North America got the NES-101, more commonly referred to as the Top Loader, while Japan got the HVC-101, more commonly referred to as the AV Famicom. Both models vastly improved upon their older counterparts and are absolutely fantastic pieces of hardware. The AV Famicom is my favourite NES hardware revision. I think it looks a little sleeker than the Top Loader and the Famicom cartridges look more at home in it than NES cartridges do in the Top Loader, because the original Famicom was also a top loading console. It retains the expansion audio channel found in the original Famicom and it has the wonderful Nintendo multi-out video port on the back. I recently imported another AV Famicom for the purpose of RGB modding and implementing it into my retro gaming setup to play Famicom cartridges on. I have done this mod in the past but I made the silly mistake of selling that console to a friend who needed an NESRGB to play on. Luckily, I love doing these mods and pretty much take any excuse to do another one. This time I thought I would document the process.
GATHERING THE PARTS
I wanted to make this Famicom the perfect machine for playing my Famicom collection on. In order to accomplish this I needed to do three things to it. The first task was to completely deep clean it. Then I replaced the capacitors on the mother board and finally, I installed the RGB video modification. This required some parts; first is a capacitor kit. Console5.com sells great capacitor kits for just about any console under the sun as well as some monitors and some other electronics. That is where I got the capacitors for this project. Assembling a capacitor kit yourself isn't too hard to do if you know what you are looking for and I have done this in the past, but I don't mind supporting a site like Console5 instead. They do great work and use high quality capacitors. They make projects like this easier for everyone while keeping the parts very reasonably priced. The second part I needed was an NESRGB kit. The NESRGB is an incredible mod kit designed by Tim Worthington that enables any model of NES to output RGB video as well as s-video, if that is your thing. I have bought several of these kits over the years from Tim's site directly but if you live in the United States you may be able to buy from a US distributor instead.
The first thing that needed to be done was to completely disassemble the console. This is simple but does require a 4.5 mm Nintendo security bit screw driver to remove the 4 main screws holding the shell together. These are easily found on Amazon or Ebay. You really need to get a set of security bit screw drivers if you plan on getting into this hobby at all, they are essential. Once you are inside the console all the remaining screws are Phillips-head. I make sure to remove the buttons and the cartridge bay from the top shell and to remove the springs from the cartridge slot doors. The AV Famicom motherboard is a work of art. Its just fun to look at and see the the chips that make it run.
CLEANING THE SHELL
Now that the console was fully disassembled the cleaning could begin, starting with the case. I simply tossed everything that is made of plastic into a sink full of warm water with a little dish soap in it and started scrubbing with an old tooth brush. I always start by washing the bottom case so that the bottom stickers do not get ruined by being in the water for too long. These stickers are very durable but it doesn't hurt to protect them this way. Some people tape over the stickers to protect them further but I find this step is unnecessary. Just make sure to dry this part off with a towel right away and the remaining parts can be left to air dry after a good rinsing. A tooth brush is the perfect tool for this job as it can get into the nooks and crannies in the plastic but it is soft enough that there is no risk of scratching the plastic.
CLEANING THE CARTRIDGE SLOT
Next I gave the cartridge slot a deep cleaning. This is one of the most important steps and I do this with every console I am going to use on a regular basis. A clean cartridge slot is key to ensuring your games work every time you put them in the console, assuming your games are clean as well. For more information on the best way to clean a video game cartridge you can check out my guide here. To clean the cartridge slot I dipped a tooth brush in 99% isoproyl alcohol and thoroughly scrubbed the pins of the connector. Then, to get deeper into the connector, I put some of the alcohol on a piece of cloth, wrapped the cloth around an old gift card and inserted it in and out of the connector. I repeated this process up and down the length of the connector until the cloth came out clean.
REMOVING THE OLD CAPACITORS AND THE PPU
With the cartridge slot and case cleaned the next task was to desolder everything that needed to be removed from the motherboard. First, I needed to remove the six electrolytic capacitors. These needed to be replaced because they were old and contained electrolytic fluid. As these capacitors reach the end of their life cycle the fluid can leak out and damage the internal circuitry of the console. These would be replaced later with new capacitors that contain aluminum instead of fluid which eliminates the risk of leaking. I also needed to remove the PPU (Picture Processing Unit) as part of the RGB mod. This is by far the trickiest part of the RGB mod and should not be tackled by beginners. It is important to use good tools and to have some significant practice under your belt before attempting this. Clearing all the solder from each pin of the PPU is tough because the holes on the motherboard are plated all the way through, meaning you need to put more heat into the board to sufficiently melt all the solder. Applying too much heat could burn and ruin the PPU.
INSTALLING THE NEW CAPACITORS
Once everything was desoldered the new capacitors could be installed. There are two interesting capacitors to take note of when doing this. The first is capacitor C5, which is tall and will interfere with the RGB mod. When reinstalling this capacitor, it needs to be laid down flat on the board as shown. If you never plan on using the composite video output of the console again, once the RGB mod is installed, you don't really need to reinstall this capacitor at all as C5 is part of the composite video circuit on the motherboard. I put it back in just in case I need it to be there in the future. The second interesting capacitor to take note of on the AV Famicom is C14. The silk screen printing on the motherboard identifies this capacitor as 1uF 50V, which was what was originally in my AV Famicom, but the cap kit from Console5 included a 47 uF 6.3V capacitor for this location. When I first saw the capacitor that came in the kit, I thought it was a mistake and I contacted Luke from Console5. He and I compared a few different motherboards and he was able to find one with the same revision number as mine, HVCN-CPU-01, with the 47uF 6.3V capacitor installed by Nintendo originally. Somewhere along the line Nintendo changed the value of C14 to 47 uF 6.3V but they didn't bother to change the value silk screened onto the board until the next board revision, HVCN-CPU-02.
CLEANING THE MOTHERBOARD
After desoldering all those pins and reinstalling the capacitors, the board was sticky with flux. This is why I saved the last part of the cleaning until this point. Cleaning the motherboard itself seems scary at first but it is really quite simple. It is perfectly fine to get electronics like this wet as long as there is no power stored in the board and power is not reapplied to the board until it is completely dry so I make sure to turn the power switch to the ON position before starting this process. This drains any residual charge stored in the capacitors. To clean the board I first doused it in an all purpose cleaner and scrubbed it clean with a tooth brush. Hitting the cartridge slot again during this step doesn't hurt.
After, I rinsed the soap away with distilled water. Regular water is fine as well but I like to use distilled water just to further prevent any residue from being left behind. Finally, I completely soaked the board with 99% isoproyl alcohol in a spray bottle, making sure to get deep into the cartridge connector. This is to displace the water as isopropyl alcohol dries quickly and cleanly while water does not. Once I was satisfied that the board was thoroughly rinsed with alcohol I shook off the excess to help with the drying process. At this point it is vital to make sure the board is completely dry before continuing, so I left it under a fan over night.
INSTALLING THE RGB MOD
At this point everything was clean and it was time to do the most fun part of this whole project, install the RGB mod. Installing the kit is fairly simple if you follow the guide on Tim's website. The NESRGB kit was designed for the original NES and in order to make it fit into the AV Famicom I needed to first install the adapter board which raises the whole kit up and shifts it to one side. This adapter also works in the NES top loader. You can see in the motherboard cleaning pictures above that in place of where the PPU was I had already installed a socket. This is where the NESRGB gets integrated into the circuity of the console and with the use of a socket it can be easily removed from the motherboard if need be. The PPU I removed gets socketed into the NESRGB main board and from there is used to generate the RGB video signal. Once that was all assembled, I wired the output of the NESRGB to the Nintendo multi-out on the console. This is a breeze on the AV Famicom because the red, green, blue, and c-sync pins are present but unused. I decided to not install a colour palette switch on this console because I found I never actually used it on the last NESRGB mod I did and I like the default palette. I also always try to avoid putting holes in the console shell if I can help it.
All that was left now was to test and reassemble the console. The NESRGB can output either 75Ω c-sync or TTL c-sync and whichever you prefer is selected by jumper J8, open for TTL and shorted for 75Ω. All of my RGB SCART cables are wired for TTL c-sync so I left jumper J8 unsoldered. Just to be safe I always test the c-sync output of my RGB modded consoles to make sure it is at a safe voltage level for all of my video equipment. To do this I hooked the console up to an oscilloscope as well as my Sony PVM-8044Q and tested. As you can see below the SCART cable reduced the c-sync voltage to a perfectly safe level, about 450 mVp-p or so, and the picture looked great. Satisfied, I reassembled my AV Famicom and played some games. This project was a lot of work, but a lot of fun and it was completely worth the effort if only to play Akumajō Densetsu in RGB, with all of it's expansion sound glory.