In transmit nothing on the IC3 changes.George,
IC3 looks as if it has failed. If pins 1,2 are high then pin 1 should be low.
What are the voltages on Q1,2,3?
Also it looks as if IC1 is not sending a TX signal to IC3 and that Clk2 is not turned on for TX.
Is it going into TX mode? Does IC1 pin 3 go low when the "Key" switch is pressed?
73 Alan G4ZFQ
IC3 Voltages LCD unplugged: