NTSC Nintendo 64 RGB Booster
UPDATE - if you're having trouble find the transistors, check for an alternative. Before performing this mod, maybe you should try the recommended RGB mod.
Another update! viletim on the gamesx forums has designed an alternative RGB Amplifier, looks interesting!
Getting an RGB signal from a Nintendo 64 is not always easy. Once you've found a compatible NTSC N64, performed the RGB mod on it, you may be disappointed that the picture is too dark.
Credit for this mod must go to Mr. B. and Waltarzar for the original diagram, and whoever is hosting it over here (just in case that site ever disappears, here's a mirror). So there you have a complete list of necessary components, once you've got a Gamecube RGB lead (3rd party may be better, as the official one already has a tiny circuit board built into it) your only worry is fitting all of that into a Scart plug. mmmonkey designed the following layout for a little circuit board, and will attempt to talk you through making the circuit and lead!
mmmonkey bought a PAL Gamecube RGB lead from Play-Asia.com, it's good for this mod, the 3 wires carrying the RGB signal are actually Red, Green and Blue - not that important, but it does make it a bit easier. Plus, it already has 3 100uF 10v Capacitors, they are smaller than any that I have bought separately, or seen in other Scart leads. So take the Scart lead apart that you intend to use, and check which capacitors it's already got, and remove them ready for re-use, or throwing away. If the Capacitors have a small piece of rubber tubing over the leg/s, then keep it for use later on. Also make a note of which colour wire was attached to each capacitor/pin, pin 15 is the Red signal, 11 is Green and 7 is Blue.
In addition to the components listed on the original guide, you'll need a small piece of Strip board/Vero board. Cut the board so it is 9 holes wide and 4 tracks high, trim the board so that it is as small as possible. You'll need to cut through 3 of the rows, normally when you cut this board, you cut through the holes, but for this circuit, we want the board to be as small as possible, so we're going to cut between the 3rd and 4th set of holes, and the 6th and 7th set of holes.
The copper strips are the underside of the Vero board, components are pushed through from the other side, then soldered onto the copper tracks. The first components to solder on are the 1K5 Ohm resistors, bend the resistors into the following shape.
The first resistor needs to be parallel with the board, push it through the following holes, but bend it flat as shown, then solder it to the copper side of the board
Push the second resistor through the following holes, and solder it into place, repeat for the third resistor.
You could insulate the resistors, if you have some heat shrink tubing, cover the resistors, cut to length, and heat as needed (or struggle with electrical insulation tape if you don't have tubing), also notice how the legs of the resistors have been trimmed, you should do this for everything you solder to the board.
Next up is to cut some pieces of wire, to help you, you could use Red, Green and Blue wire. Push each wire through the following holes and solder into place (refer to the diagram above if you're unsure of the correct holes). Make sure each wire is too long (about 5cm is more than enough), they will be trimmed to the correct length later.
Bend the transistors so they look like the following, it's easiest to bend the outer legs first, then straighten the middle leg. Be very careful not to bend them too many times as they will snap.
The transistors are fitted as shown below, make sure you get them the correct way round (study the diagram above, where the flat side is facing, it is away from the resistors)
