scantronic 9448 fault?

we have been having powercuts lately and the alarm is about 10 years old i think when the power goes the outside rings and really funny it rings like a school bell not the normal sounder you would hear on a alarm it has no strobe either should i get a new battery and im thinking of buying a new bell box because when the alarm goes off people will just be thinking ive got a bell can anyone advise

Bill
January 2010