Originally Posted by centuryvrproductions
When I press and hold the Mon to open the squelch, I hear the button press Tone come out of the speaker, the Bsy light flashes as it is recieveing, but no audio at all comes through.
just a click when the squelch opens thats it.
When you power up the radio or press a button and hear a strong beep as normal, this indicates the audio PA amp is OK. By pressing and holding the monitor button you see a flashing "busy" light but no open squelch audio out the speaker.
OK, the audio starts at the detector chip on the RF board. This is raw detected audio, unsquelched and unfiltered. It is then passed over to the logic board where the squelch gate lives and the filters are that shape the audio. Not much on the logic board to oops on. If there is a problem there it would be at the component level and you would need a schematic and test equipment to troubleshoot.
I'd say you are missing the detected audio or the squelch indicator from the RF board to the logic board. This is a common problem with this era radio, a bad connection between the two boards. Easy fix though if this is the problem. Remove several torx head screws from the RF board and lift it out. Use a pencil eraser and some contact cleaner to scrub the pin connectors that go between the two boards.
This usually fixes most problems....