If for some reason your tranceiver seems to have lost its audio it could be to the 5 or 8v mic voltage being lost. Some times this happens if you have shorted the lines out by accident, or by trying to fit another microphone, that was incorrectly wired up.
Simple strip the radio down, hmmm easier said then done, then locate the board with the mic connector on, and you will see some surface mount components on it; diodes and switching
transistors, check them for open or short circuits, or maybe even a blown track.
You will need a good small tipped solder iron to be able to fix this problem.
Note: this voltage is different to the one that makes the leds light up, on the DTMF microphone
so don't think because the DTMF mic light up, all is ok with the voltage.
Hope the info helps.