What was found
PILOT REPORTED THAT ENROUTE, THE NR 1 NAV RADIO TRIPPED OFF-LINE AND HE CONTINUED INTO CPR USING NR 2 NAV. AFTER LANDING PILOT STATED HEARD A POP AND SMELLED A BURNED ODOR - BUT WAS UNSURE IF THE ODOR WAS FROM FOREST FIRES IN THE AREA. STATED THAT THE NR 1 NAV SWITCH WAS HOT TO THE TOUCH AND WAS NOT RESET. FLIGHT LANDED WITHOUT ANY FURTHER INCIDENT - NO EMERGENCY WAS DECLARED. MX TROUBLESHOOTING REVEALED THE NR 1 ESSENTIAL BUS SWITCH SMELLED BURNED AND HAD VERY HIGH RESISTANCE WHEN OHM CHECKED AND INSPECTED. MX R & R NR 1 AVIONIVS BREAKER/SWITCH IAW MM 24-50-00. ALL WIRING WAS INSPECTED BEHIND DISTRIBUTION PANEL WITH NO PROBLEMS NOTED OR INDICATED. SYS FUNCTIONAL CHECKS WERE GOOD.