Batboard

heres one for yuh. mcs2000 uhf 450-520 trunk mount, basic head 50 watt. when the mic is on the hook the radio has audio, when i take it off hook there is no audio however the busy light is lit.

Sounds to me like "handset" is enabled. I think this is a menu option. It mutes the internal speaker when you take the handset out of cup to use it telephone style.