Check the fuse holiday lights usually have cartridge fuses in a small compartment in the cord plug behind a sliding door.
Easy way to check xmas lights.
Open the sliding compartment door and remove the fuse s.
Then connect the first bulb to the first socket and repeat the process for the second one.
Either way you are testing 25 of the 50 bulbs without breaking into a sweat.
If the original neon bulb lights move halfway down the remaining part of the set and try again.
Learning how to change a fuse in christmas lights is simple but if your strand of lights does not appear to have accessible fuses move on to step 4.
Light testers search for the point in the string where the voltage changes between a good bulb with current flowing and a problem area with minimal current.
Then remove the middle bulb of the string and check it with the multimeter.
If the other neon bulb lights then the problem is in the first half of the set.
Then connect the second bulb to the socket in the middle of the string.
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