What was found
PDX FLIGHT NR 2094, DURING CLIMB-OUT, ELEVATOR HORN HEAT CAUTION LIGHT ILLUMINATED, FOLLOWED BY LEFT STALL WARNING TANK 1 AUXILLARY PUMP LIGHT WENT OUT ALSO. MAINTENANCE INSPECTED AND FOUND NR 1 PROP DEICE BRUSH BLOCK ARCING/OVERHEATED WHICH CAUSED A AND B PHASE CB'S TO TRIP IN NR 1 AC CONTACTOR BOX. REPLACED NR 1 BRUSH BLOCK PER AMM 61-10-11-000-801 AND 61-10-11-400-801. REPLACED TRIPPED FUSES GROUND RAN AIRCRAFT AND OPERATIONAL CHECKED ALL SYSTEMS MENTIONED ABOVE AND PROP HEAT. ALL CHECKS GOOD. AIRCRAFT RETURNED TO SERVICE.