As a collector, I own a First Alert SC9120B Smoke and CO Alarm.
However, when I apply power to it, such as a 9V battery, it does a continuous beep. It is not that regular T3 or T4 pattern you hear when it’s in alarm, it isn’t neither the detector malfunction signal (3 chirps), the end of life signal (5 chirps), nor the low battery signal, just a solid beep and it doesn’t stop until power (or battery) is disconnected.
What does this mean? Is my detector broken?