Hello all! I just registered on the forum and this will be my first post!
I just got an old famicom (HVC-CPU-GPM-02) and am about to mod this to my liking. I am currently stuck at the options I got regarding the audio. I plan to order the NESRGB with the power/audio board to go with it.
I'm about to add regular controller ports to the console with support for zapper and mic by a toggle switch.
I've also learned that my revision of motherboard has a bad value on a resistor before sending the audio to the cart.
If looking at the circuit on the famicom board I would change resistor R7 on this schematic
http://nesdev.com/Ntd_8bit.jpg
Mind, on GPM-02 this value is 43K (checked!)
43K would make sound come out too low before mixing with cart/everdrive.
If I was to use the NESRGB audio circuit and get sound directly from CPU, where do I connect the cable from the mic (with R3 in line) and where to swap resistor(s) for a trimpot? The only thing I found in this thread was the fix for the AV famicom but that fix does not make use of the power/audio board shipped with the old famicoms, right?
A schematic for the power/audio board for the NESRGB would be very helpful!
So, how to do to keep mic and be able to adjust sound level before the mixing with expanded sound from cart?