What was found
DURING CLIMB, FLIGHT CREW REPORTED A PITOT HEATER FAIL INDICATION AND STAND-BY AIRSPEED INDICATOR WENT TO ZERO. AFTER RESETTING THE SYS, WARNING RETURNED AND CREW REPORTED SEEING AND SMELLING SMOKE, FOLLOWED BY STAND-BY PITOT HEAT CIRCUIT BREAKER TRIPPING. MX WAS UNABLE TO DUPLICATE DISCREPANCY. SYS WIRING AND SYS COMPONENTS INSPECTED AND FOUND TO BE IN GOOD CONDITION. A VERIFICATION FLIGHT WAS PERFORMED WITH NO ABNORMAL INDICATIONS. ON LATER FLIGHT, CREW REPORTED SAME PITOT HEAT FAIL MESSAGE. MX ACCOMPLISHED SERVICE LETTER SL750-30-08 FOR REPLACEMENT OF THE ANTI-ICE PCB AND NO FURTHER INSTANCES OF THIS DISCREPANCY HAVE BEEN REPORTED.