sounds like your problem lies on the trace of pin 5, which is the RX/TX switching pin.
look at the schematic, at the components that are connected to the pin 5 trace, and make determinations based on metering the components either in place or out of circuit.
basically it's C133, R162, TR35, or the wiring on the CB/PA switch.
i know you said that you already replaced TR35, but don't take it for granted.
remember that when you key the mic, with the radio in CB mode, it grounds the emitter of TR35.
check to see if this pin is grounded when the radio should be in receive mode.
if it is, pull TR35 out and check the trace that connects the emitter to the TX pin of the mic jack, through the CB/PA switch. if that trace is still grounded, that points to your switch wiring.
if it's not, it points to TR35.
LC
