FC Twin snes board pinout aka: getting rid of the NES board

[grahf]

I decided to start tinkering with my FC twin today. It was easy enough to remove the NES board, since the first 10 pins bypass it. The way the power switch works, is it just directs power to the right 7805. There are two, one for the NES part, and the other for the SNES part & video encoder. So if you wanted to power the SNES section, all you need to do is put 5v into pin 5 and ground pin 4. You can then pull RGB from pins 6-9. The first 10 pins are:

1 unregulated + in from wall plug
2 unregulated + out to 1st (NES) 7805
3 unregulated + out to 2nd (snes) 7805
4 ground
5 5v in from 7805
6 red
7 green
8 blue
9 sync
10 sine wave output (used by video encoder on the power board. Not used if your just pulling RGB)
11 goes through .1uf ceramic cap (104) and a 33k resistor, then joins with pin 13
12 goes through .1uf ceramic cap (104) and a 33k resistor, then joins with pin 14
13 goes through .1uf ceramic cap (104) and a 33k resistor, then joins with pin 11
14 goes through .1uf ceramic cap (104) and a 33k resistor, then joins with pin 12

(the numbers dont line up obviously, but I just wanted to show which way I was counting)



Audio pinout
In order to completely remove the NES board, you have to add a few ceramic capacitors and resistors inline. If your still using the power board, you can then add the L and R signal into the next two spots on the power board. NOTE: that its taking 4 pins for audio and ending up with two. See the picture below:




Now, everyone should have all the information they need to pull RGB and audio off the SNES portion. Keep in mind that the audio coming off of the SNES board is low power but it should still be strong enough to use as is, depending on what your feeding it into.
On the power board, there is a generic 2904 op-amp (audio amp). Here is a datasheet for this type of amp: http://www.ortodoxism.ro/datasheets2/3/ ... dwruwy.pdf
If you need it, you can just put the opamp on a tiny daughter-board.

[shmagoogin77]

nice work

[Turbo Tax 1.0]

yeah i got that far but the audio was to much work, i just hacked up the nes part and made it ~ an inch squared

mmm, fctwinp so small

[grahf]

What part of the audio circuit was giving you trouble?

From looking at it, there is a generic 2904 audio amp on the power board. The signal coming off the snes board may be too weak to use without this. Its a simple chip, just power, audio in L&R, and audio out. I'm going to pull it off the power boad and put it on its own little daughter board. I just need to take another look at everything when i have time and trace the L&R audio signals coming off of the SNES.

[Turbo Tax 1.0]

all i know is it looks like a few ceramic caps, resistors, and an oscillator, are needed from the nes board

[sammy]

Is it possible to reuse the NES alone or would you need the extra power board?

[grahf]

I figured out the audio pinout. I'll update my original post in a few minutes with the information. Perhaps someone can make this a sticky.

Sammy, you should be able to use the NES board on its own, but im not 100% sure yet. You just have to supply 5v to it. It has its own audio and video out, that shouldnt have to go through the rear power board at all. But, it shares the controller inputs with the snes board. The SNES and NES controllers use the same ICs, but the SNES just has two of them (for the extra buttons). I dont know how the controller signals reach the nes board since i havnt traced them yet. Maybe in the future.

[sammy]

The ability to use the Snes without the Nes has given me an idea. I've tried connecting everything just like Grahf said and it worked perfectly so I thought of using the NES board as some sort sort of extension on the bottom of the portable. I don't play a lot of NES games so taking that part away makes it a lot sleeker, however if I get the urge to play some NES games I can plug in the extension (with a connector) to play nes games.

[Life of Brian]

I know this is a ridiculous bump, but why on earth is this not stickied?

[themadhacker]

good point.

[eurddrue]

I know this is a ridiculous bump, but why on earth is this not stickied?

Don't bump threads over 6 months old unless you have something to contribute.[/just kidding]

[themadhacker]

hey, only I get to day that!

no, I'm just kidding.

[eurddrue]

hey, only I get to day that!

no, I'm just kidding.

That was your 1337th post ahahahahaah

[themadhacker]

1337 what?

[Kurt_]

Way to ruin it.