Please help find the manual for this First Alert Smoke Detector

Inseting batteries
Inserting batteries in BRK First Alert, model no. 9120B

Changed Batteries, won't stop chirping
First Alert 9120B Smoke Alarms-We have 4 of these & they all started chirping at the same time. We changed all the batteries. 2 have stopped chirping but 1 is still chirping about every 30 seconds and the other beeps every minute or so. Help, I'm going crazy and my dog won't stop barking at the chirps. Thanks, Liz

replace battery
I need the manuel to show me how to replace the batter in model No. 9120B

Green LED
I have 6 of these in various rooms. They are all wired to AC and therefore should have a constant green LED lit. However 2 of them were blinking green. Also, occasionally some of the 6 sound a single beep...not sure which ones were doing it. I called tech support who said that the 2 were apparently "latched" and they were the ones that were beeping sometimes. The manual describes what latching means but doesn't say how to unlatch them. Her instructions were: unscrew the detector from its base and remove the AC connector, swing out the battery drawer to disconnect the battery, press and hold the Test/Silence button for 20 sec., close the battery drawer, press the Test/Silence button and it should alarm (3 beeps). Reconnect the AC power and the green LED should stay on constant. Finally, reconnect the detector to its base.