A real retro one this, & oddball too. The Nintendo Famicom is basically the Japanese version of the NES. It does have superior sound capabilities, but essentially it's an 8-bit NES. The problem with these is, they are NTSC only only supporting RF out...all you'll get over here is a crappy black & white image.
Enter, the AV mod. Here's the Famicom, some slight differences to the NES as you can see...the joypad cables are integrated into the console [non removable] & are quite short. Pad 2 also has a built in mic which you can use in certain games.
The video signal is taken from pin 21 of the ppu [picture processing unit]
It's then fed into this circuit I built. Most guides detail soldering these components directly onto the board, but I chose to use a small section of proto board. It's better for the console, & the video picture will be clearer because the signal will be cleaner.
5v & ground are taken directly off the power regulator, & fed appropriately into the circuit
The video output is then fed to an rca jack. I've one or two spare scart/av blocks, so I stripped one down & cut it to size rather than ordering chassic mounted ones. This will be much more sturdy, & better shielded
That's basically it, the rca jack is connected to the new circuit I built. Time for a quick shake down
What do ya know, it works!
Ok, back to work. I need sound. It's taken off of pin 46 of the underside of the cart connector, & a ground too.
It's then fed to the appropriate connectors on the back of the rca jack
With everything checked & working, I mounted the rca unit into the console by drilling three holes
Time to mount everything inside, & hot glue ot down. This is important because the cart eject mechanism is a moving slider & can easily snag/crush the new cables.
That's it, it's a nice little mod all in all. Took a while to get the technicalities correct because there's a good few board variations. Sometimes different value caps yield better results than others because of this. Also, there's an additional cap in place between pins 20 & 22 of the ppu to eliminate white bars on bright screen. I forgot to take pics of that bit, but it's done.
I used this guide, & the thread linked within for reference - http://jpx72.detailne.sk/modd_files/fc/avmod.htm