Changing Retro

Posted on Sep 30th 2013 at 05:19:36 PM by (wildbil52)
Posted under mods, n64, RGB

RGB is the holy grail of display formats for retro video games.  The people who prefer hooking their consoles up via RF do so for nostalgia, not image quality. The folks who use composite and S-Video are on the right track, they want a higher quality picture, but RGB is better.

Component video is not RGB.  While component video cables are Red, Blue, and Green in color, they still send combined signals over the same cable which results in a slightly lower quality picture.  They typically carry YPbPr signals.
In YPbPr:
Y (Red cable) carries luma (luminance/brightness) and sync (synchronization) signals
Pb (Blue cable) carries the difference between blue and luma (B-Y)
Pr (Green cable) carries the difference between red and luma (R-Y)

The information for Green is not sent because it can be determined with the blue, red, and luma signals.

An RGB signal carries the Red, Green, Blue and Sync data on four separate cables.  If you are interested in more of the technical aspects of RGB or if you would like to see some screenshot comparisons, I strongly recommend you check out http://www.retrorgb.com

On to the mod...

IMPORTANT! This mod restores RGB output to the N64 A/V Out.  You will need an RGB monitor and the appropriate cables in order to hook your system up to an RGB monitor.  LOTS of info on the cables required can be found at http://www.retrorgb.com

Not every N64 is capable of outputting an RGB signal.  In the US, the early N64s had a video chip on the motherboard that was capable of outputting RGB so all you have to do is connect the RGB outputs on this chip to the RGB spots on the video output terminal and you have an RGB capable N64.  Nintendo eventually changed the video chip on the N64 to one that did not natively output RGB so the mod is only possible on early N64s.

How early?
If your N64 has a serial number that starts with NS1, you can mod it to output RGB
If your N64 has a serial number that starts with NS2, you cannot mod it to output RGB


There is always a (slim) chance that the guts of your N64 have been swapped so another way to check is to open your N64 and look at the motherboard revision. 

If your motherboard revision is NUS-CPU-01, 02, 03, or 04, you can mod it to output RGB.  If it is NUS-CPU-05 or higher, you cannot
You can see your motherboard revision just above the cart slot when you take the top cover off of an opaque system:


and you can see it on a clear system without taking the shell off, just remove the power supply:


You can also swap the guts of an older N64 into the shell of a newer model that you really want to get RGB from.  For example, I love the Jungle Green N64 but my Jungle Green model is an NUS-CPU-05.  I swapped the guts from an 03 into the Jungle Green shell and presto! Jungle Green RGB Wink

Tools you will need
4.5mm security bit to open the N64
Phillips screwdriver
Soldering Iron with a fine tip (I prefer a chisel tip for this job)
Solder and flux
Thin gauge wire, 26 gauge works well
Hot glue gun OR electrical tape

OPTIONAL but HIGHLY recommended
RGB amplifier chip THS7314DR installed onto a
SOIC 8 to DIP 8 board
Three 75 ohm resistors with the lowest tolerance possible

Once you have determined that your N64 is capable of RGB, Strip the system down to the motherboard. There are LOTS of screws so make sure you take a few "before" pics or organize them in a way that will make it easy for you to put them all back in the right places.

This is the chip you are looking for


The three indicated legs output the signals for R, G, and B.  All you have to do is connect three wires from these three legs to the RGB posts on the A/V output area on the back of the board.





If you are not installing an amplifier, ignore the Power and Ground posts, just connect three wires from the RGB legs on the front to the RGB posts on the back and you are done. 

Let me tell you why you really should install the amp, though.  The RGB signals that the N64 outputs are quite weak.  Without an amplifier, you will have to crank up the brightness and/or contrast every time you want to play your N64 on your RGB monitor.  The amplifier is inexpensive and easy to install.  Here is what it looks like assembled:


But Bil, why do I need resistors on the output side?
You need the resistors because the amplifier amplifies the signal just a little bit too much.  Without the resistors, you would have to slightly lower the contrast/brightness on your monitor.  Adding the 75 ohm resistors means that you will not have to fiddle with the dials at all.



I do sell assembled amps with wire so that you can just solder 8 wires to the N64 motherboard and be done.

I find it easier to start on the back/underside of the board..


so that I can set the board into the bottom case and finish up the front


You can now test the system to see if you were successful.  Pro Tip Make sure you put the jumper or expansion pak back in the system before you power it on.  I forgot and just connected power and a/v and got a little scare when the screen was black.  After I put the expansion pak in, I got this image.


And I didn't think that title screen could have looked any better.


Once you know you were successful I recommend applying a little hot glue from a glue gun to the three connections on the top of the board just for a little added security.

After I put the rf shield, heatsink, and all of the screws back in, I wrap the amp in a little electrical tape for a little added protection.



And that's it!  Please feel free to ask any questions below or via PM.


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Comments
 
Awesome tutorial. Very simple - too bad I need a new solder kit. Pet project for the weekend, I guess.
 
Great tutorial. I'd love to do this. I find the image my N64 produces appalling. Worse than my SNES, somehow. Everything dances and jiggles, it's annoying.
 
Thanks for the tutorial.  I'd love to see how Ocarina of Time looks on RGB.
 
Ocarina is a good on on RGB.  I'm finding out that N64 games are a little hit or miss.  RGB really shines at 240P and most (possibly all) expansion pak games are bumped to 480P when the expansion pak is used.
 
Correction, 480i

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Like many of the people who visit this site, I am a lifelong gamer who loves and appreciates classic gaming as well as the current generation. When I started collecting games, I realized that some of the stories of my collecting might be interesting, educational, or just plain funny. The stories that I share here are meant to entertain as well as inform and they are all 100% true, which is why I include pictures.

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