Things You'll Need
Replacement fuses (typically 3A)
Hum tracing device
Christmas light repair gun
Net Christmas lights are strings of lights held together in a square net pattern. They are designed to wrap around bushes and trees, making it easier to cover them with light in a uniform pattern. The main problems that occur with net lights are that the netting is prone to tangling and a few burnt-out bulbs can cause the entire strand to go dark. You can repair these problems using a few electrical tools.
Untangle the net lights---if they are tangled---then move the bulbs and strings around each other, until the squares are untangled.
Plug the lights into an outlet plug. Note any bulbs that are burned out. If the net does not come on at all, you may need to replace the fuse. Remove the fuses inside the plug and replace them with new fuses. Check the light again to see if any of the bulbs work.
Remove the bulbs from the sockets to test them for connectivity. Place a hum-tracing device at the base of the wires coming off the bulb. If the wire hums, that bulb is still good. Make sure to press the bulb down tightly into the socket, so that it connects with the string of wires.
Mark any bad bulbs with a permanent marker. Use wire cutters to gently pull the light bulbs from the socket. Replace the bulb with a new bulb. Press it down firmly, so that it connects with the wires. After every replacement, plug the light string back in, then remove it. This not only test the lights, to ensure they are working, it also helps prevent the new bulbs from over-heating and going out.
If you cannot find the correct size of bulb to replace the burned-out ones, which is often the case, you can use a light tool that looks similar to a gun. Hold the gun up to the burned bulb and pull the trigger. This will fuse the shunt inside the bulb with the rest of the wires in the net, which will help the other lights to burn around the burned out bulb. This also prevents other lights from overheating and burning out.