NTSC Nintendo 64 RGB Again!
The N64 console doesn't officially support RGB. It can be added to some models of the console, it has to be an NTSC console (although mmmonkey has read that there is an early French Secam model that is also compatible), be careful though - as there are a couple of different NTSC versions, only the earliest ones are compatible.
Unfortunately there isn't a easy way of identifying if a console is compatible without actually opening it up (some people say that the later limited edition coloured consoles are generally not compatible). You have to take your console apart (Gamebit needed), remove all of the heat sinks and shielding etc until you can see the upper side of the motherboard. If your console can be modified then the chip at location U1 will have "VDC-NUS BU9801F" printed on it, if it can't be modified then the chip at location U4 will have "MAV-NUS RS5C282 (or RS5C382)" written on it.
UPDATE - some extra info from Link83 about serial numbers, motherboard revisions and a whole heap of stuff here, this chap knows his stuff!! Getting the serial number is now a good way of finding if it's RGB'able!
Some clever people are still making new RGB mods and Amps and for the NTSC N64, I saw this on GamesX, which in turn links back to another site which has two RGB Amp mods. AND, I've just heard that Lin83 is working on another RGB mod, looking forward to it :-)
I wanted to try one out and decided to go with the one that uses the least amount of components. And now, thanks to this mod, I can use my official Gamecube RGB Lead not only with my SFC, but also my RGB N64, this makes me happy for some silly reason!!
This mod uses an SMD chip, that means it's small, about 5mm long. So it's a bit fiddly, but not impossible. It's the THS7314, an amplifier with 3 inputs and outputs - very handy for RGB. Here it is, my photo editing skills used to the max combining a diagram and photo showing the pinout and orientation!
This mod is so simple, it doesn't really take much explaining. I started off with a small piece of Stripboard, and made some cuts with my scalpel. Take a look at the photos below and you'll see the cuts and how they seperate the chips legs. (Actually, if I was doing this again, I'd probably just turn the chip upside down and solder directly onto the legs, that's probably easiest right?!)
So above you can see I seperated the left and right sides of the board. Then cut along the middle copper track twice, and picked a small strip out. Here's how the chip looks when I test fit it. You can see each chip leg now has it's own copper track to attach onto
Now just add some solder to the ends of the copper tracks to solder wires and resistors onto.
Now I've added the 75 ohm resistors (I removed these later! So that I could put them on at a different angle). The resistors are on the ouput side of the Amplifying chip. Then wires are soldered into place - Red, Green, Blue talk for themselves, Yellow will be for +5v and Black - Ground. The round disk, that's the 0.1 uF Capacitor, doesn't matter which way around it goes, it bridges the power and ground.
Now the fiddly bit, attaching that TINY chip. Again, add some solder to the copper tracks to solder the chip legs onto...
Okay, carefully turn your chip upside down, with a small, very small amount of solder on your iron, tap the underside of each of your chips legs. Top up the small amount of solder on your iron every couple of legs. You want a tiny amount on the chip leg, not a blob.
Now hold the chip in place, and quickly touch each leg with your soldering iron. It should be just quick enough to heat up the solder on the leg AND the solder on the board and melt them together. Perhaps do two opposite corners first so that the chip can't shift around as you're solder.
That's the board finished. Unless you're me trying to photograph it and write notes. I then test fitted it to the N64 motherboard and decided to change the resistors so that they are bent at a right angle. And swap the order of the RGB wires so that the correct colour goes to the correct point on the board (not strictly necessary, it's just so that my photo's show the correct signal, I can of course use any colour wire I want!!) I've used C124, C125 and C126 here, but you can use the R8, R9, R10 points if you prefer, both lots connect to the video chip on the other side of the board.
I stuck the board to a flat bit of motherboard with a piece of insulation tape rolled back on itself to make it double sided stickey (very professional!), I also added stuck of strip of tape to cover the board underneath the resistors. I forgot to photo the insulation tape that I put on the metal shielding where the RGB Amp will be near it.
Update, the next N64 I modified, I did just stick the chip upside down to the motherboard with double sided tape, and solder directly to it. Used enough double sided foam tape to hold the resistors in place. I also used it as an excuse to use my newly purchased Kapton tape, really thin insulation tape that's a disgusting yellow colour, handy for guides though as you can see through it, you can of course use any insulation tape.
It's not easy taking photo's of the TV, but here's a couple (the LCD doesn't have those vertical lines in the image, it's just the photo).
A close up using my VGA scaler with ScanLine Generator also.
You can see the points I used for the RGB inputs for the chip from the photos above.
Here's a diagram I found on my computer showing the AV socket points. Some nice person has labelled the RGB points (sorry if I've pinched your photo, let me know and I'll credit you). You can also see Ground points (G) and the +5v point (I trimmed my wires too short and decided to use points nearer to my circuit board, found them with my multimeter)
If you have issues with the picture wobbling on your TV, please look here and here for more info.
UPDATE
John emailed me after he had some issues with
cross-hatching on the screen after doing this mod and then updated me with some
extra info after he had a play around, he pointed me to
this forum thread.
Here's a copy of what's needed to be done:
i) Amplify the RGB lines with the THS7314 chip
ii) Then to get rid of the awful X pattern hatch effect on the screen, I cut the
composite video sync trace (PIN9 on the multiout marked V) and ran a wire from
PIN7 on the multi out (marked Y) to PIN9.
Note: This is almost like the guide here, but
linking Pins 7 and 9 instead of 3 and 9)
iii) Once completed, you can use either the PAL SNES Scart cable or the PAL
Gamecube Scart cable.
The most important point to make is that since you do not need to tap the C-sync
from Pin 3, there is no need to rebuild the C-sync circuit on REV04 mother
boards.
Thanks John :-)
Ooh, and then there's this VGA mod which sounds very interesting!
Summary of Components needed
3 x 75 ohm resistors
1 x THS7314 chip
Wire! I used Kynar
