Hi All

We have an old ADT Accord XPC home alarm system that's been excellent.

Recently we've had the alarm go off around half an house after leaving the house, then it resets itself.

I've done some tests and have come to the conclusion that the problem is with our front door Reed Switch sensor.

My issue is tyring to identify the door sensor I need to order - as you can see by the photos, I've taken it apart and mine has two additional resistors.

Every one I've ordered so far doesn't have these resistors and wont work with my alarm system.

Any help in identifying this door sensor and the replacement I need would be much appreciated.

Thanks

what you have there is a standard contact where the installer has added the resistors they are 1K 1K

ie Knight D20 5 Terminal Surface Contact [D20] - £1.14 : , Best Price Promise

so you can replace the contact and re add the resistors or

if you use a d75 it has jumpers to select the resistors

Knight D75 Surface Contact with Selectable Resistors Knight D75 Surface Door Contact with Selectable resistors [D75MULTI] - £3.50 : , Best Price Promise