Need help with famicom AV mod.

hi all, so basically I am confused as to what I need to do to mod a famicom with composite video and audio.

I found this site which seems to explain a bit but I am just not sure what I actually have to do.

So what I can tell is I have to lift a leg of a transistor then solder a resistor then the + leg of a cap then another resistor going vcc and the - leg of the cap goes to composite out?


Then for audio, is it best to pull the mono sound from pin 46? of the cart connector then split it out to two rca plugs to get mono over both left and right speakers??

What is the list of components I'll need to do this mod?



With my system I get jailbars running on RF, what are the chances of the jailbars coming up with the av mod.


Also I'm using a FDS is there anything I will have to do different to get full compatibility with this mod?


Thanks

 

I wouldn't use that mod as some people (including myself) have had problems with it. Instead I would use Calpis' mod, which is the same circuit used in the AV Famicom. I don't have a diagram handy but it's easily to follow.

First you'll have to lift pin 21 of the PPU, then solder the base of your transistor to it. You can use a 2N3906 transistor but I would suggest using the 2SA937 already found in the Famicom (you'll need to desolder it of course). Then you need to solder ground to the collector pin of the transistor. Next thing you'll need to do is twist together the positive leg of a 220 uF capacitor and one leg of a 330 ohm (300 ohm works fine too) resistor, solder them together, and then solder the combination to the emitter leg of your transistor. Finally, wire the other end of the 330 ohm resistor to 5V and a 110 ohm resistor to the negative leg of the capacitor. From the other end of the 110 ohm resistor is your video output.

Pin 46 would work fine for audio, and since you get external audio that way you won't have to worry about compatibility with the FDS.

As for jailbars, you'll get some from the AV mod but not as much as you would with RF. If you want to reduce the jailbars, you can put some copper tape over the PPU and solder a wire to ground on the tape.

 

thanks!, so parts wise I'll need:

either the 2N3906 from the mobo OR a 2SA937 transistor , so the 2N3906 is just part of the RF circuit?

220uf cap

330ohm resistor or 300ohm

110ohm resistor


and for the audio just a 220uf cap

also I plan to use a 3.5mm 4 pole jack and place it in where the rf socket is, do you think that will be the best solution?

Thanks agian

 

For video I used this schematic from Console5. I ended up having much less Jailbars with this than with wathever was suggested by the folks on Famicom world.

http://console5.com/wiki/File:NES_Toploader_AV_Schematic.png

 

cool that seems pretty good, so I lift pin and connect it to either a 2N3906 from the mobo OR a 2SA937

 

It's the other way around, the 2SA937 is what's already there on the board.

 

ok, what type of transistor will i need if i dont use the one from the board ,npn?

 

The 2N3906 as mentioned before, which is a PNP transistor.

 

ok, so I have acquired the parts, here is the receipt.


They gave me two transistors?
They said they didn't have one of them so they replaced it with a substitute. but there should only be one in this right? I did write on that schematic that max war linked that ha the transistor I needed and an extra cap...

 

Also a 100uf cap on pin 22 and pin 20 of the ppu will help reduce jailbars.

Pin 20 is ground.

 

I've done the mod but I am getting a faint buzzing noise from the speakers..

 

Make sure the mic on controller 2 is off.

 

fixed it,, it was the connector I was using lol