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Smoke Alarm BRK Model 9120B Teardown

The BRK & First Alert 9120B was introduced in 2004 as a replacement for the 4120B [3]. The old plastic ionization chamber with a metal top was replaced by an all metal chamber to shield electrical noise. The integrated circuit (IC) was upgraded. The BRK 9120 can be interconnected to other compatible BRK Smoke Alarms [2].

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Front of BRK 9120 Box.
Front of BRK/First Alert Model 9120 Box.
Back of BRK Model 9120 Smoke Alarm
Back of BRK/First Alert Smoke Alarm Model 9120.
Inside the BRK Model 9120 Smoke Alarm
Inside the BRK/First Alert Smoke Alarm Model 9120.
Component Side of PC Board - BRK Model 9120 Smoke Alarm
Component Side of PC Board - BRK / First Alert Model 9120 Smoke Alarm.
Back Side of PC Board - BRK Model 9120 Smoke Alarm
Back Side of PC Board with Surface Mount Components- BRK/First Alert Smoke Alarm Model 9120.
Radioactive Source, Americium 241- BRK Model 9120 Smoke Alarm
Radioactive Source, Americium 241 - BRK / First Alert Smoke Alarm Model 9120.
Piezoelectric Disc- BRK Model 9120 Smoke Alarm
Piezoelectric Disc - BRK/First Alert Smoke Alarm Model 9120.
Zero Ohm Resistor in BRK Model 9120 Smoke Alarm
The 9120 uses Zero Ohm Surface Mount Resistors for Jumper over PC Traces. The solder joints are coated with Paraffin Wax.

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