First Alert Smoke Alarm 9120B Battery Replacement - IFixit

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Introduction

Follow this guide to fix your First Alert Smoke alarm. This fix will stop the First Alert Smoke alarm from beeping when your battery is low.

Make sure you have your 9V battery in hand and a helper to make sure that you do not fall from your stool. These alarms are usually found mounted into your ceiling so please take precautions when unmounting the alarm.

As you will be working with wires, please make sure that you are gentle with the alarm since it is easy to break the covered wires if you are too aggressive with it. All of these steps should require very little strength. If you find yourself needing to force things into place, please review the steps to make sure you are properly uninstalling/installing the smoke alarm.

What you need

1. Step 1 Battery

   

   • Remove the alarm by rotating it counter clockwise in the mount.

   • The alarm should fall off once rotated enough. The cable should be the only thing holding it in place if done correctly.

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