I'm working on something similar.? It looks like Q6 is part of the ?B's mic pre.? When TX goes high, Q6 turns on and passes the signal into the mixer and so on.? RX also goes low and turns off Q70.? So if you wanna skip the ?B's mic pre you have to turn off that signal during RX.? This is because TX and RX share all that mixing and filtering and modulating stuff that I don't quite understand yet.
If someone who knows what they are talking about can confirm this, I'll give myself another high five.
Arvo W0VRA