I'm working on a handheld ham radio, its lost all audio input. Emergency tone transmits but no audio. I've narrowed it down to be what I believe to be an mic amp but I'm struggling to find the part on the interwebz. I've attached a picture red is the amp and yellow is the mic line into the circuit. I'm completely green to component level stuff kinda self learning with trial and error. I've got a decent bench going just not sure where to probe without a data sheet.. im sure some of you can do this in your sleep so please excuse my water behind my ears im still a baby.