How to Troubleshoot and Repair Christmas Lights
If you have ever tried to find the faulty bulb in a string of mini-Christmas tree lights, you know how time consuming and frustrating that can be. In the past, the easiest way to get the lights working again was to replace the string with a new string.
No matter how careful I was the previous year when I took down the Christmas lights and stored them away, several strings always developed problems. Whole sections would go dark because of a problem with one bulb and a section might have as many as 35 to 50 bulbs. The only quick way to find the faulty bulb was to replace them one at a time until the section lit up, or so I thought until my wife bought me a "LIGHTKeeper Pro" last year as a birthday present and an early Christmas present. I was skeptical until I used it the first time. I had tried many gadgets that were suppose to help you fix Christmas light strings, but none of them worked reliably. The LIGHTKeeper worked every time as the user manual claimed it would. It was well worth the $30 my wife paid for it.
The Mini Light String Bulb
One burned out bulb is not supposed to make a whole section go dark, but that is what usually happens. As you can see in this drawing, miniature holiday light bulbs contain a "shunt" that connects across the base of the bulb's filament. The shunt is designed to energize when a filament burns out. The purpose of the shunt is to maintain the continuity of the series circuit, so the remaining bulbs remain lit. More often than not, the shunts never work as they are supposed to, which cause the section of bulbs to go out. The LightKeeper Pro Quick Fix Trigger repairs the malfunctioning shunt by sending a shaped, electrical pulse through the faulty bulb, clearing the malfunctioning shunts.
The LIGHTKeeper Pro
The LIGHTKeeper Pro is a mufti functional tool and offers the users several options for locating and repairing defects in light strings. The "Quick Trigger Fix" is its handiest and quickest method, but the tool also acts like a continuity tester, voltage detector, fuse tester, and bulb tester. The LIGHTKeeper Pro uses an Integrated Circuit (IC) chip to detect the minute electromagnetic field emanating from any wire that has an electric current flowing in it. A steady beeping from the tool indicates the presence of this current/voltage.
The Quick Trigger Fix Using The Socket Connector
The most common cause of problems with light string is one or more defective light bulbs. The easiest way to locate and repair this problem is by using the light socket connector on the front of the LIGHTKeeper Pro.
Remove any unlit bulb from its socket. When the lights are already on a Christmas tree, remove the most easily accessible unlit bulb from the string, and unplug the light string from the wall outlet or extension cord. Make sure the socket is free of tinsel, needles, or other foreign matter.
Plug the light socket in the light socket connector on the front of the tester. With the light socket firmly seated in the tester's socket. Plug the light string back in the wall receptacle and pull the trigger on the tool three or four times (three or four times is normal.) The unlit section should light up.
Unplug the light string from the wall receptacle, unplug the light socket from the tool, and replace the bulb you removed earlier. Plug the light string back in the wall receptacle. Check the light string again for unlit bulbs and replace with them with new bulbs.
Using The Continuity Tester
If the lamp socket is too large to fit the socket connector, the continuity tester is an alternative method for locating the defective bulb shunt. This method works best when the light string is lying straight and flat on the floor or ground.
Plug the defective light string into a wall receptacle or extension cord.
Press the black button located on the topside of the tool down to activates the continuity checker. The "Red" LED should come on letting you know that the continuity tester is on.
Place the nose of the tool against the bulb closest to the plug and listen for a beeping sound from the tool. If the beep sounds go to the next step.
If the beep is not present, reverse the plug in the receptacle or extension cord and test again. With this test, polarity does matter. If there is still no beep, you probably have a bad fuse in the plug. If the beep is present proceed.
Starting a couple of inches from the first bulb, place the nose of the tool about ½ inch from the wire. Move the tool along the wire until the beeping stops. The bulb you just passed is the problem.
Replace the bad bulb and all the light should light up.
The continuity checker can be used to locate fault in icicle light sets too. If the continuity fails after one of the hanging icicles is passed, the bulb tester will have to be used to find the bad bulb in the icicle strand.
Bulb and Fuse Tester
The fuse and bulb tester located on top of the tool is self explanatory, so I will not explain it here.
Photo credits LIGHTKeeper Pro media package