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Smoke Alarm - First Alert SA303 Teardown


The SA303 is one of BRK's economical Ionization Smoke Alarms. Walmart sell it for under $8. The SA304 adds an escape light. The SA305 comes with a lithium battery.
 
Limitations:
 
(1) It is powered by a 9-volt transistor battery; it cannot be connected to 120 volts AC.
 
(2) It is a single station alarm; it cannot be interconnected to other BRK smoke alarms so if one alarms, they all alarm.

For Maximum Resolution, Click on the Body of the Picture.

First Alert SA303 Front of Blister Packaging.
First Alert SA303 Front of Blister Packaging.
First Alert SA303 Back of Blister Packaging
First Alert SA303 Back of Blister Packaging.
Front of First Alert Model SA303.
Front of First Alert Model SA303.
Backof FirstAlert Model SA303.
Back of First Alert Model SA303.
 Inside the First Alert SA303.
Inside the First Alert SA303.
  Componet Side PC Board for the First Alert SA303.
SA303 Component Side of the Printed Circuit Board (PCB).
Back of FirstAlert SA303 PCB.
Back View of the Printed Circuit Board for the FirstAlert SA303.
Micro Chip RE46C122.
BRK uses an Application Specific Intergraded Circuit (ASIC), RE46C122, manufactured by Micro Chip - Data Sheet
First Alert SA305.
First Alert Model SA305 in Blister Packaging.
First Alert SA305 Lithium Battery
First Alert SA305's Lithium Battery.
2006 First Alert SA303
Back of 2006 First Alert Model SA303.
Top Collector Plate Spot Welded
In the 2006 version of the SA303, BRK Spot Welded the Top Collector Plate to the PC Board Jumper (J1).
Bottom Collector Plate Spot Welded
In the 2006 version of the SA303, BRK Spot Welded the Bottom Collector Plate to the Smoke Alarm IC.
Allegro 1897-0177-000 IC
The the 2006 version of the SA303, BRK used an Allegro 187-0177-000 Application Specific Integrated Circuit (ASIC).