A modding board to achieve RGB video on some early NTSC models by using TI's THS7374 video amplifier.
⁓ Designed with ♥ in Germany ⁓
You can order the PCB directly from OSHPark.
Of course, feel free to use the gerber files with any manufacturer of your choice.
Use 0.8mm board thickness to ensure an easy and clean installation.
This modification only works with NUS-CPU-01/02/03/04 main board revisions!
Also, verify that your main board has a 'VDC-NUS'/'VDC-NUS A' chip (U4).
If that's not the case - stop here! Your console is not compatible with this modding board!
Use a pair of pliers to bend away the tab which is located at the MultiOut area.
This avoids the shielding from hitting the modding board later.
- remove R1, R14, R15, R16, C22
- isolate the bottom side of the modding board to avoid any shorts
- solder the modding board onto the pins of the MultiOut
- solder a wire from the via next to R8 (N64 main board) to pad 'R' (modding board)
- solder a wire from the via next to R9 (N64 main board) to pad 'G' (modding board)
- solder a wire from the via next to R10 (N64 main board) to pad 'B' (modding board)
- solder a wire from the via next to R16 (N64 main board) to pad 'CS' (modding board)
Double-check continuity between connections:
- 'R' (modding board) ⇄ VDC-NUS(A) pin 17 (N64 main board)
- 'G' (modding board) ⇄ VDC-NUS(A) pin 19 (N64 main board)
- 'B' (modding board) ⇄ VDC-NUS(A) pin 21 (N64 main board)
- 'CS' (modding board) ⇄ VDC-NUS(A) pin 14 (N64 main board)
Check for shorts to VDC-NUS(A)! The vias you solder to are located directly beneath that IC.
It's ridiculously-simple to short something when the exposed conductors are a little bit too long!
The THS7374 has a low pass filter on each of the four channels which can be turned on by shorting jumper 'J:LPF' on the modding board. This is mostly needed if you wire the console directly to a flat-screen TV. There's no need for the low pass filter on analogue devices.
If you use an OSSC or a Framemeister, it's better to use their filter options.
You will need a RGB cable with 220µF electrolytic capacitors on each of the 'R', 'G' & 'B' lines. The positive end is facing towards the console.
This modding board is designed to output TTL level C-Sync directly at the MultiOut of the console.
With that in mind, make sure you're using a suitable cable with a 470Ω resistor on the sync line to use it with most consumer products (like TV's, OSSC, Framemeister)!
I am not responsible for any damage to you, your devices or anything else!
If you do the modification, you do it at your own risk and responsibility!
Most of the credits should go to borti4938. He has made the actual (slightly different) circuit and inspired me to design this board. Thanks man! Thanks Bob, for your awesome and informative website RetroRGB!
And of course, thanks to the whole retro gaming community for keeping the spirit alive!