Hello 25537: Trouble shooting from behind the keyboard isn't easy or the way to do it.
Here are some suggestions that might help.
Does the S-Meter work showing local stations are on the air? If so maybe a possible the Squelch is turned up too high, or the external speaker jack will only work with a external speaker. Worth trying a external speaker out.
By operating the controls and switches on the radio, will this bring up the audio?
While the radio is on, can you lightly tap the radio and listen for recived audio?
The Push to Talk (PTT) switch in the mic may have some sort of problem, try a another mic?
Is the RF Gain is turned all the way down (counter clock wise) ?
Can you switch thru the channels and then hear just a few channels?
A technican will put in a signal at the antenna jack and trace the signal thru the radio to find were it isn't, and repair the radio. May not cost too much.
Hope this helps, as not being there to share war stories, talk and annoy everyone for hours on end, and leavy way too late.
Jay in the Mojave