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
5 5v in from 7805
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)
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.