What was found
IAH-CREW REPORTED SMOKE IN COCKPIT AFTER ATTEMPTING TO START THE APU, A/C LANDED AT IAH WITHOUT INCIDENT. MX INSPECTED THE A/C AND FOUND THE APU START CONTACTOR TO HAVE A MELTED LUG AND HEAT DAMAGE TO THE BUSS BAR AND LINE CONTACTOR. MX REMOVED/REPLACED THE AFFECTED START CONTACTOR, BUSS BAR, AND LINE CONTACTOR, OPERATIONALLY CHECKED A/C, AND APPROVED FOR RETRURN TO SERVICE.