What was found
PHL-FLIGHT 3722 EMERGENCY LIGHTS FLASH ON AND OFF DURING CLIMB (ALL LIGHTS FLASH DIMLY). MAINTENANCE TROUBLESHOT AND FOUND NR 2 TRANSFORMER RECTIFIER UNIT LOAD VALUE LOW. NR 2 TRU, NR 2 PROPELLER BRUSH BLOCK AND 1 RT PROP HEATER LEAD REPLACED DUE TO VOLTAGE DROP ON RIGHT SECONDARY BUS CAUSING EMERGENCY LIGHTS AND OTHER INDICATIONS TO FLICKER. OPERATIONAL CHECK OF NR 2 PROP HEAT AND EMERGENCY LIGHTS NORMAL. AIRCRAFT RETURNED TO SERVICE.