The sequencer is designed to feed the control module and input signals to the gain module in the correct sequence, reducing the emissions of signals that occur in the transceiver during the transition from reception to transmission.
Also on this board is the main attenuator, which reduces the output power of the transceiver from 100 W (5, 10, 50) to the power required for the amplifier's input. Two more corrective attenuators, which serve to co-adjust the gain, which varies on different bands.
Time charts taken with an oscilloscope.
" + 12V TX " terminal
" V k1 " terminal
" G Stop " terminal
"+ 12V TX Bias " terminal