C182G INSTRUCTOR PLT AND NEW PLT OWNER WERE ON A FACTORY DELIVERY FLT WITH A BRAND NEW ACFT WHEN THE AUDIO PANEL FAILED; CUTTING OFF ALL RADIO COM TO THE ACFT.

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THE FLT WAS AN EXTRA TRAINING FLT ON A CUSTOMER'S NEW GARMIN G1000 EQUIPPED ACFT. AS A FLT INSTRUCTOR WORKING OR ACFT MANUFACTURER; I WAS ASSISTING THE OWNER OF THE ACFT ON HIS TRIP FROM THE FACTORY TO A PVT FIELD NEAR NEW ORLEANS; LA (LS40). WE DEPARTED ON THE SECOND LEG OF OUR TRIP FROM SHREVEPORT; LA; AT APPROX XA30 ON AN IFR CLRNC FOR LS40 IN CLR VFR AT NIGHT. APPROX 1/2 HR AFTER DEP; THE AUDIO PANEL FAILURE OCCURRED WITH LOUD STATIC FOLLOWED BY SILENCE AND THE LOSS OF ALL XMIT; RECEIVE; AND INTERCOM FUNCTIONS. THE SYS HAS A BACK-UP ANALOG MODE FOR THIS SIT SO I INSTRUCTED THE OWNER TO TURN OFF THE AVIONICS BUS #2 (THERE HAD BEEN SOME FLICKERING OF THE AUDIO PANEL LIGHTS JUST PRIOR TO THE FAILURE) IN ATTEMPTS TO USE THE BACK-UP MODE THROUGH THE PLT'S SIDE HEADSET. THE AUTOPLT IS ALSO PWRED BY AVIONICS BUS #2 AND THE OWNER DID NOT REALIZE THAT HE HAD TURNED IT OFF; SO I PROCEEDED TO HAND FLY THE ACFT FOR THE REST OF THE FLT. AFTER APPROX 1 MIN; WE TURNED THE AVIONICS BUS #2 BACK ON AND THE AUDIO PANEL APPEARED AS THOUGH IT WOULD FUNCTION BUT DID NOT; INCLUDING THE ACFT'S BUILT-IN MIKE. AT THAT POINT; I INSTRUCTED THE OWNER TO SQUAWK 7600 AND BEGAN TO USE THE MFD TO DETERMINE WHERE WE WOULD DIVERT. I CHOSE THE NATCHITOCHES MUNICIPAL ARPT FOR OUR DIVERSION; APPROX 5 MI S OF OUR POS. THE APCH AND RWY LIGHTS WERE ON (LATER LEARNED TURNED ON BY OTHER PLTS FOR ASSISTANCE) AND WE CIRCLED ABOVE THE FIELD LOOKING FOR TFC AND DSNDING INTO THE PATTERN. THE WINDSOCK WAS NOT LIGHTED WELL ENOUGH TO SEE; SO I USED THE G1000 WIND VECTOR INFO TO CONFIRM THE APPROPRIATE LNDG RWY. AFTER LNDG; WE TAXIED TO A HANGAR FOR SHUTDOWN AND WERE MET BY RESCUE PERSONNEL. AFTER SHUTDOWN; THE CUSTOMER TALKED TO THE RESCUE PERSONNEL AS I CALLED FORT WORTH FSS (DERIDDER WAS THE APPROPRIATE STATION; BUT MY CELL PHONE CONNECTS ME TO FORT WORTH) AND EXPLAINED WHAT HAD HAPPENED AND THAT WE HAD LANDED SAFELY. THE FSS REPRESENTATIVE ASKED FOR THE IDENT FOR THE ARPT; AND UPON TURNING ON MY FLASHLIGHT TO FIND IT ON MY CHARTS I NOTICED SOME SMOKE COMING FROM BEHIND THE INST PANEL (ALL ELECTRICAL EQUIP HAD BEEN OFF FOR ABOUT 2 MINS). THIS WAS CONFIRMED BY A FIREMAN WHO HAD BEEN LISTENING TO ME AS I TALKED TO FSS. THE SMOKE DISSIPATED AND THE EVENT WAS OVER AT THAT POINT. MY ONLY SUGGESTION IS THAT THE STANDARD FSS NUMBER HAVE A MENU ALLOWING THE PLT TO CHOSE THE CORRECT ROUTING FOR HIS CALL. WE CHOSE TO DIVERT DUE TO THE POSSIBILITY OF FIRE AND THE INABILITY TO GET LCL WX AND TURN ON THE RWY LIGHTS; AND THE SYS WORKED JUST AS IT WAS DESIGNED TO. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE INSTRUCTOR PLT WORKS FOR THE MANUFACTURER AND HE TEACHES GND SCHOOL ON THE GARMIN G1000. HE CHKS OUT NEW ACFT OWNERS. THE RPTR CONTACTED THE MANUFACTURER ENGINEERING UNIT; AND GAVE A DETAILED DESCRIPTION OF WHAT HAPPENED. THE MANUFACTURER HAS BEGUN AN INVESTIGATION. THE RPTR SAID THE MANUFACTURER REPLACED THE AUDIO PANEL AND SOME SOFTWARE. THE BACK-UP ANALOG MODE DID NOT RECOGNIZE THE FAILURE; AND DID NOT GO INTO THE BACK-UP MODE.