The house alarm started going last night at 10.00 and did stop for about 15 minutes inbetween. It was doing this up unill 3.30 this morning. Tried everything and it just went on and on, there are three red lights on the system box and the sensor in the front room doesn,t light up. The alarm is a 9200 and its an old one as it was here when I moved in...can it be fixed? Is it expensive to replace it?