Open the Interlogix Box as pictured below..

  1. Check the DC voltage on the battery terminals (1) this should equal 12V
  2. Check the AC voltage after the Transformer (2) this should equal 18V
  3. If the voltages on (2) equal 0V AC, then check the AC voltage both before and after the fuse in the grey fuse holder (not pictured but it should be roughly located in the blue box area)
  4. If there is 240V AC before the fuse but 0V AC after the fuse, replace the fuse, spare fuses are taped to outside of the door of the Interlogix box.

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