What was found
DESCENDING THROUGH 600FT ON APPROACH LEFT GEN OFF AND LEFT AC PWR FAULT. MESSAGES ILLUMINATED ON OAP AFTER ABOUT 1 MINUTE WE LOST ALL AC PWR. SWITCHED EMERGENCY POWER SWITCH TO "ON" BUT GOT NO POWER RESTORED UNTIL THE APU CAME ONLINE. PER ASAP, EMERGENCY DECLARED. PERFORMED ENGINE RUN TWICE. NO FAULTS. WHILE INSPECTING LEFT GENERATOR CEU MAINTENANCE NOTICED SLIGHT ELECTRICAL SMELL. REPLACED LEFT GENERATOR CEU AND COTA PRECAUTIONARY, PER MM. REMOVED AND REPLACED #1 CABIN PRESSURE CONTROLLER PER MM. SERVICED NR 1 AND NR 2 VSCF'S. OKAY FOR SERVICE.