I'd appreciate any troubleshooting ideas.... When I push the copilot PTT switch (Two wires), I don't get a side tone, other aircraft / ATC can't hear me (I do not get "carrier no voice"), and there is no voice transmission through the intercom. The T light in each radio lights up and I do hear a click in the headset. Have tried different headsets (all work on pilot side). PTT works. Both radios have same issue and work fine, including intercom, from pilot's side. Have tried intercom without PTT and copilot side doesn't work either. Equipment consists of 2 KX 155 TSOs, KMA 24 audio panel, Sigtronics SPA 400 TSO, and new wiring.