While the N64 was an excellent console in its time, there is a huge problem associated with it. Namely, it will not work with any newer HDTV. The reason for this is that almost all consoles made by Nintendo were designed to output colors separately, bu this system was not built with this capability.
This instructable will show you how to mod your N64 so that it can be used on a new TV, with all of the original cables.
This is not a very easy mod, so if your soldering skills are not up to par, I would not recommend it. There are small components involved that can be damaged.
Thanks to retrorgb for their instructions on their website. This 'ible is based off of that, with a few modifications that make it a bit easier.
An N64 console (must be model number NS1******). list of compatible models http://retrorgb.com/n64rgbcompatible.html
An N64 RGB amplifier chip. You can get this on ebay for about $15, or on the retrorgb website for $23.
4.5mm large Nintendo game bit to open the console
3 very thin 20+ gauge wire. They can be any color, but it is easiest to use red, green and blue.
Optional: Helping hands are useful, especially if it has a magnifying glass and a light source. You will be working with tiny components
Step 1: Opening the Console
Open the memory expansion port on the top of the console, and pull out the memory pack or expansion pack, whatever you have in there.
Using the large Nintendo bit, unscrew the 6 screws on the bottom of the console.
Pull the top half off of the console, and put on the side.
To remove the shield from the motherboard, there are 5 different types of screws. I drew different colored circles around them to help you put it back together.
Red= long silver screws
Yellow= long gold screws
White= thin gold screws
Purple= short gold screws
Black = short gold screw with washers
All of these screws can be removed with a Philips screwdriver. An electric screwdriver is not recommended, as many of them are powerful enough to crack the plastic threads.
Step 2: Soldering the Chip
Solder the red, green and blue wires to the corresponding part of the mod chip.
Helping hands work very well here to hold everything in place. Keep in mind that the alligator clips can damage the board and wiring, so I just used some folded up paper to protect it. You can use anything like that.
Next, flip the motherboard upside down and put the chip onto the upper left corner of the board. You will see there is only one place it fits.
Place a piece of electric tape between the chip and the board. Many chips come with a piece of non conductive tape already in place.
There is no need to solder all of the pins, only the ones I have circled in red.
Step 3: Soldering the Wires to the Board
Now comes the hard part.
The 3 wires need to get soldered to the board.
There are 2 places they can be soldered; choose either one.
On top of the board, they can be soldered directly to the pins coming out of the chip, as displayed on the picture. Pin 17 is red, 19 is green and 21 is blue.
If you choose that option, you will need to wrap the wires around the board, so I find it easier to use the next option.
Solder the wires on the bottom of the board where I zoomed in on the pic. Place the wires directly into the holes: blue is R10, green is R9 and red is R8. The ends of these wires need to be VERY short. If they are sticking out on the other side, they can short the board. It will likely not destroy it, but it will not work until this is rectified.
After you are done, cover any solder points with electrical tape just in case, and secure the excess wire to the board with tape.
At this point you can close up the N64, as you are done. I prefer to test at least once with the naked board before I close up, just in case I need to fix anything.
Step 4: Play!
You are now ready to play your favorite old games!
If your TV has only HDMI input, you can use an AV to HDMI converter, they are about $10-15. This will not give you better picture quality, as it is not true HDMI. But it is easier for many people to use this type of cable system.
If you want to go for higher picture quality, you can try to get an SCART adapter from Europe, and then use an SCART to HMDI connector for the TV. This gives a sharper image, but is significantly more expensive (expect at least an additional $35 for the setup).