How does the fuse check ? You looked at it?
Why was there a total power shut down?
Why did it false alarm? Thought about that?
Get a new battery.
The strobe will not activate in a total power off, the external bell/sounder should.
So you have two issues, a duff panel battery and a duff sounder SAB.
A quick search here would have found this information.
Alarm
November 2011