What was found
CREW SET UP IAW DDG 49-11-01. CREW ISOLATED THAT LT PNEUMATIC & RT UTILITY. CREW STARTED NR 4 ENG. DURING START, AT THE TIME, NR 4 ENG GOING TO TAKE OVER POWER BY GEN FROM ENGINE. THE ACFT STARTED TO SHED LOAD POWER. THEN LT SIDE WHICH IS POWERED BY LT EXT POWER 1 SHUT OFF COMPLETELY. ACFT WENT DARK THEN CAME UP ON BATTERY POWER. BOTH THE EXT POWER 1 & 2 SHOWED LIGHTS AND AVAILABLE. CAPT SELECTED EXT PWR 1 & JET POWERED FOR APPROX 30 SEC THEN SHED LOADED. NR 4 ENG STILL RUNNING. CAPT ELECTED TO SHUTDOWN NR 4. A STRONG & PREVALENT ODOR OF ELECT BURNING. FOLLOWED BY A LIGHT HAZE OF SMOKE IN COCKPIT. PERFORMED SMOKE OR FUMES IN CABIN INSPECTION. NO FAULTS FOUND. PERFORMED FIM 21-00 TASK 810. NO DEFECTS. WORK DONE IAW AMM 05-51-56. PERFORMED POWER CHK ON APU 1 GEN TERMINAL T1, T2, T3 & FOUND ABNORMAL VOLTAGE IAW WDM 24-21-51 & FIM 24-21 TASK 805. REPLACED APU NR 1 GEN. OPS TEST NORMAL IAW AMM 24-21-03 AND AIPC 24-21-03-01.