I have an SC1200 and one of the door/window sensors stopped working even with new batteries. I replaced it with an extra one I had and I was all good again. Now 4 months later the sensor in the same location stopped working so I replaced the batteries and it was fine for about 2 days, then it came up as low battery. I replaced the batteries again but it still came up as low battery (yes I checked the batteries and they are full charge). I replaced the sensor with another extra one (Got about 10 of them in 2009) put the new batteries in and nothing, no light, no chime, it seems to be dead right out of the box. I then checked the remaining 7 brand new sensors and none of them work. Did they have problems with these when I bought them and I just happened to pick the ones that worked to start out with by some fluke?
I have tried brand new batteries of two different brands and checked all of them with a multimeter for voltage and amperage and they all check out fine. How could I possibly get 8 sensors that are DOA?