You do come up with some winners.
But, must ask, does this radio have FM?
Why? The relay CROSSES over two sets of contacts - one is for a jumper - like normal routing - while in TX the audio is routed around that.
Question of FM is - one jumper in the center of the board - may route to the front of the radio - to a pot of the front panel. Which would kill AM audio because the relays' contacts switch out the jumper and it goes to the middle of the board. So if radio is in normal mode, the jumper by the AM regulator is one thing - but TX? I see the contacts route elsewhere possibly to front panel.
If it was FM you don't need the AM regulator - you can bypass it and allow Audio amp or mic amp to deviate the PLL -so if it was talkback, the speaker wiring would be involved more - and I don't see that. And no dropping resistor to be seen...so FM mode perhaps to kill AM regulator and send a DC flat power to AM regulator as switched...
It's why I asked about FM and front panel...