AS WITH ALL MY VIDEOS I TRY TO GIVE THE MOST INFORMATION IN THE LEAST AMOUNT OF TIME AS POSSIBLE SO I DONT WAIST YOUR TIME. IN THIS VIDEO GO OVER HOW TO DIAGNOSE AND FIX OR REPLACE A FIRST ALERT FIRE/ CARBON MONOXIDE ALARM MODEL 9120B OR SC9120B. USUALLY IT'S JUST A BATTERY BUT DID YOU KNOW THERE IS 2 OTHER WARNINGS THAT YOU MIGHT GET ON THESE ALARMS I DIDN'T.
