Luciano,

Thanks for pointing out the pin 9. I setup one of my alarms to cycle the relays every second and I measured the voltage when the field collapses. Based upon what we discussed here, I should have expected this. The voltage when the field collapses is 64 volts but when pin 9 is connected, it is only 12.5 volts. Of the 90 units I have in the field, none of them have pin 9 connected. I guess it is not a matter of if but when they will fail.

I will let this test alarm cycle until the ULN2003A fails. At least I will have an idea when I should expect them be returned for warranty repair. Also, I will post when the ULN2003A fails if anyone is curious. If there is anything positive to come out of this, at least I caught the issue now with 90 alarms in service as opposed to 1000 alarms in service.

Thanks again for pointing that out. You probably saved me a lot of headaches wondering why my alarms are going to fail in the future!