What was found
DURING TAXI, ELECTRIC LIGHT ILLUMINATED FOLLOWED BY CABIN LIGHTS FAILURE. ACFT GROUNDED. R & R R607, NO HELP. WHILE T/S USING SSM 24-51-11 PAGE 103, SHEET 2 FOUND BURNED TERMINAL RINGS AND WIRES ON B-PHASE. REMOVED POWER DISTRIBUTION PANEL P91 IAW AMM 24-21-21-000-801. INSTALLED PDP IAW AMM 24-21-21-400-801, ALL OPS CHECKS COMPLETED, ALL OPS NORMAL.