Ya I guess this radio does have talk back. Either way TB or PA will accomplish the same thing. I think it also has RF power in diagnostics, but I'm not sure how reliable it is, but the OP can try it.
I know nothing about CB except at my former quarry job when this happened it meant our squelch was turned up too high. You could hear the other trucks talking, your transmit light would blink but nobody could hear you.
I'm sorry, I posted incorrectly. The talk back works through the internal speaker. The PA works through the external speaker. The external speaker has to be plugged in the PA jack on the back of the radio.
Oh come on midnight, pull the radio, take it to any shop and have them test it, you can afford the $20. Chances are it has an audio issue internally,. Just so you know the dual antenna system is a combination am/fm-cb antenna system and it is best to run a separate coax to the left side abs mount a new antenna for just the cb, leaving the right one for the am/fm radio.
Maybe use your fuel points and pick up a new radio for free at a truck stop? I picked up a Uniden PC78 for free with my points at a T/A 3 years ago. It was on sale for $80 and it always works when I need it. I use it as a backup radio for my big radios and when I have to get in a spare truck with a less than stellar antenna. https://www.amazon.com/Uniden-PC78L...3DT3,B01MQDYF66,B00A1VSO9M&srpt=TWO_WAY_RADIO JD
I never use the am/fm. If I was going to continue this career beyond the next 10 days I would get it checked out. I’m guessing it is an internal fault.
Have you tried the cb selftest... Also have it checked because for some reason some of the cobras will over time get off frequency... display shows ch19 but it's actually transmitting on just above or below that
I did all of the self tests and calibration described in the owners manual. I think it is probably an internal fault of some sort.