What was found
LEFT PACK FAILED ON CLIMB THROUGH 700 FOLLOWED BY SMOKE LIGHT ON MAP PANEL AND SMOKE AURAL WARNING. RETURNED TO SFO. REMOVED AND REPLACED LEFT AIR CYCLE MACHINE WITH SERVICEABLE UNIT IAW MM 215005, OPS CHECKS GOOD AT THIS TIME. (P/N 22045402) ON, (S/N 87303) ON, (S/N 100534) OFF.