What was found
LAX - ON CLIMB-OUT LWR AFT CARGO FIRE WARNING LIGHT CAME ON TWICE. NR 1 FIRE BOTTLE DID NOT DISCHARGE. NR 2 FIRE BOTTLE DISCHARGED NORMALLY. SMELL OF ELECT BURNING IN THE COCKPIT. RETURNED TO LAX. FOUND BOTH NR 1 AND NR 2 FIRE BOTTLES DISCHARGED. NR 1 BOTTLE AFT DISCHARGE PRESS SW INSTALLED IN NR 1 FWD POSITION. REPOSITIONED TO THE CORRECT POSITIONS. NO EVIDENCE OF FIRE SMOKE OR CHARRED WIRING FOUND. 4 HOUR OPS CHECK WAS OK. FOUND NR 3 AFT SMOKE DETECT LIGHT CAME ON AND STAYED ON DURING OPS CHECK. REPLACED NR 3 AFT SMOKE DETECTOR. (M)