Use Light Keeper Pro by squeezing its trigger to send an electrical pulse into a defective bulb on a string of Christmas lights. The technology works because the shaped pulse you send clears the shunt in the defective bulb that is preventing the other bulbs from lighting up.
When multiple bulbs go out at a time on Christmas lights, it is typically because one of the shunts inside a bulb has failed to energize. Because of this, electricity is unable to flow through the now defective bulb to light up the others in the series of lights. The Light Keeper Pro allows electricity to complete the circuit, providing light to the other bulbs.
The Light Keeper Pro allows you to identify the defective bulb with a Continuity Detector/Voltage Detector with an integrated circuit chip to help detect where electricity has stopped flowing on a string of lights. The device consistently beeps while you scan the string of lights, indicating the presence of electrical flow. It stops beeping in the area where the defect is, giving you the chance to examine if the bulb can be replaced or simply secured if it is loose.
If the bulb cannot be salvaged, remove it from the unlit section, and plug it into the Light Keeper Pro's Socket Connector, lining up the metal contacts. Then, pull the trigger until the light set, plugged into the AC outlet, lights up. Now, unplug the light set, and place the bulb back into the empty socket.