What was found
BOS - FLT632 - ON CLIMB-OUT FROM CLT EN ROUTE TO BOS, WITH ENGINE ANTI-ICE ON, CREW HEARD A POP NOISE ALONG WITH A STRONG ELECTRICAL BURNING SMELL. CREW SHUT OFF LEFT PACK AND SMELL DISSIPATED. PASSENGER REPORTED A PUFF OF BLACK SMOKE CAME OUT OF LEFT ENGINE. CREW FOUND THE LEFT NR 2 STANDBY IGNITION CIRCUIT BREAKER POPPED. TURNED LEFT PACK BACK ON. OPERATION NORMAL. MAINTENANCE INSPECTED NR 1 ENGINE IGNITION SYSTEM. ACCOMPLISHED AUDIBLE IGNITION CHECK PER MM 74-00-00-705-001. OPERATIONAL CHECK GOOD. RAN ENGINES AND PRESSURIZED AIRCRAFT. CYCLED THERMAL ANTI-ICE VALVES FOR CONTINUOUS IGNITION. NO DEFECTS OR SMELL NOTED.