My video doorbell stopped working. I called tech support and I unistalled doorbell from outside and connected it via USB Cable on the wall. The doorbell lit up and started working. Reinstalled doorbell and it still didn't work. Called an electrician and he said the transformer in the doorbell burned out. Electrician installed a new transformer and the doorbell began working. Electrician left and 20 minutes later I had to call him back because my doorbell stopped working again. He found out the the Lorex doorbell had burned out the new 24 volt transformer. Called Lorex Technical Team to ask about polarity issues as recommended by the electrician. I was given the run around and the couldn't comment on polarity. Now I have an electrical bill and still no video doorbell. I am disappointed in LOREX.