What was found
LIGHTS FLICKERING IN CABIN DURING TAXI. PERFORM NR 2 GEN FEEDER CABLE INSPECTION PER MAINT TIP. CHECK NR 2 IDG OIL LEVEL ON SIGHT GLASS, AND VERIFY COWLS LATCHED WHEN DONE. MADE INOPERATIVE NR 2 IDG PER MEL 2420D. FOUND THE CABIN OVERHEAD LIGHTS ONLY FLICKERED WITH SET IN LOW BRIGHTNESS ON NR 2 GEN ONLY. REPLACED IS THE EXTERNAL POWER SUPPLY UNIT PCN 565-9003. SWAPPED GCU'S FROM NR 1 TO NR 2 ENG PER MM, NO HELP. INSPECTED FEEDER CABLES AT UPPER CONNECTOR, NO DEFECTS FOUND. REPLACED IDG PER AMM.