It could also be that the breaker has tripped at the panel. If the breaker switch is a GFCI style switch, pushing the reset at the switch solves the problem. Sometime there are multiple lights on a circuit. If, for example, there were a breaker switch wired to supply a series of lights, then all of the lights in that series would be out at the same time if the problem were at the breaker.
It is interesting to note that each year the bulb bases seem to differ, and typically it is impossible to get direct replacements another year. Probably we could remove the bad bulb from its base, and re-use that base with a new bulb. But using a bulb from a different set often has sad consequences.
Open the wiring junction box on the fixture and find the two wires that are connected to the thermal protection device. Disconnect the two wires and remove the thermal protector. Take the thermal protector to the hardware store so you can purchase the properly-rated replacement.
Good article, but like almost every other instructional topic on fixing busted Christmas Lights there are no instructions on how to actually get those little darn fuses replaced. What I mean is its easy enough to get the male electric cord plug compartment door open and the old fuses out, but getting the new Christmas light fuses to fit into the slots in many cords I’ve had is d@m near impossible. I have searched high and low throughout the internet and never found a video or article or any other webpage reference to issues getting the replacement fuses to properly seat into the fuse compartment slots. If someone could write about this subject and provide solid instruction on the best tools and methods to get those pesky little fuses to fit into the slots it would be a gem of a resource for those that do not want to throw strings of christmas lights away simply because the new fuses are so difficult to get to fit into the fuse slots in the electrical plug of the christmas light string.
Install the new springs on the trim or cover and re-install the trim or cover to the body of the fixture. Using needle-nose pliers to secure the springs to the inside of the fixture will make the job easier.
Over time, the contacts inside the socket can become corroded or filled with dirt and grime. This can prevent proper contact between the bulb and the socket, which often results in no power to the bulb.
This past year we bought a very cheap string with a “snowball” diffusing coating that started blowing 4 or 5 bulbs a week. Even our usual full replacement string would have been consumed in 5 or 6 months. Eventually, I took the plug and socket from a replacement string, and put a silicon power diode in the circuit. Any diode over, say, 200V (peak-inverse-voltage) and 1A current should work (and if it fails, the lights just go back to full brightness). The diode can be oriented in either direction and placed in either line. In my versions, clear heat-shrink tubing covers the connections and the diode itself.
The lights that I have are somewhat more complicated. They have a little plastic box with an IC and some transistors etc and a push button switch. They can flash with different sequences. There are 4 circuits of 4 different colour leds. My Multimeter doesn’t register ac or dc voltage coming out on the 4 lines. Maybe there is high speed switching. I have an oscilloscope, but didn’t want to have to get it out!
Another issue seems to be warm-up time: All incandescent bulbs increase their resistance as they warm up. But even bulbs with the same ultimate operating voltage can warm up at different rates. And if a fast-warming bulb is placed in a slow-warming string, it can quickly see much more voltage than expected, and may blow out.
Before touching the metal of any wiring, be sure the power is off. You may bet your life that the power really is off when you actually just think it is. Pull the plug! The fuses are there to protect the wires, not people. Even a small current can be dangerous if it goes through a human chest.
After testing the lights and making sure the bad socket fixed the problem, consider putting in some silicone sealant (or museum wax) into the cap in order to keep moisture out and prevent the wires from corroding.
Just finished watching and reading thru the posts and have a quick question. Does the Lite Keeper work with LED Strands/bulbs. and If someone could explain the 3rd wire, as I too have this configuration. I have a prelit tree and am trouble shooting on the tree.. strands are wound into the tree, so not EASILY possible to remove and lay on floor or counter to see whole string.
Tip: If you need to unbolt the tail light assembly to change one bulb, it is a good idea to change all of them. This may save you the time and extra work as bulbs generally start to burn out around the same time.
Many strings have two separate circuits of bulbs. Within each circuit, all the bulbs are wired in series. They each see the same small fraction of the line voltage, but only as long as the bulbs operate identically. Different strings can have bulbs of significantly different resistance, yet all bulbs will operate at the same voltage, as long as the bulbs are similar within a circuit. But if we place a high-resistance (typically dimmer) bulb in a generally low-resistance (typically brighter) circuit, that bulb can see far more voltage than it was designed to handle. In that situation, the bulb may simply burn out in a fraction of a second.
I bought a new set with replaceable LEDs and took one out. The whole half string goes out. Then I went along as suggested but even knowing where the “bad bulb” was there seemed to be voltage everywhere. If an LED fails and you don’t know which one it is and there’s no test, replaceable LEDs seem pointless.
I like the idea of finding the faulty LED. But It is a little strange that taking out one of 36 LEDs will increase the current that much. If you have 36 LEDs in series and each has an inner resistance of R then the current flowing will be I=U/36R. For resistance R=U/36I. Now if we have 110V and 9ma or 0.009A in normal part, then R=110/0.324=340 ohms. So each LED has a 340ohm resistance. If you shorten one LED we will have 35 LEDs with total resistance of 11900 and the resulting current will be 9.2ma but not 12. Something must be wrong in conclusions or LEDs are connected in groups or something else.
When the trigger pulse does not work, the LIGHTkeeper PRO also has an improved hum-tracer. My old unit would just glow an LED a little brighter when it found hum. That was surprisingly hard to interpret, and especially bad outside in sunlight. But the LIGHTkeeper PRO gives an audible beep when it detects hum, and seems far more sensitive. It is only necessary to wave the unit at a bulb. And that is much, much faster than pulling each bulb wire away from the bundle.
Fuses are necessary specifically because these strings use bulbs with internal shunts. Each activated shunt reduces the string resistance and causes the string current to increase, which shortens the life of the remaining bulbs. If bulb failure is allowed to continue, the last dozen or so bulbs will go in a rush, leaving a circuit consisting only of low-resistance shunts. With low-value fuses, we can hope the fuses will blow under the high current. But if a plug without fuses is used, the wiring will get hot, the wires in a bundle could melt through their insulation and form a copper-to-copper hot arc that could ignite a fire. Never operate shunt bulbs off the AC line without low-value fuses in the circuit! Fuses are absolutely required to protect against the worst-case situation where all bulbs have burnt out and the circuit consists only of shunts.
Sometimes, if enough dust and dirt gets into the area, it can mess up the connection as well as the bulbs. You will find that occasionally going over the bulbs as well as the entire panel with a soft cloth is a great way for you to keep it from getting too out of hand. The regularity in which you do it will depend heavily on the location that the LED light panel is in. If it is in a place that is prone to dust and dirt, then you will find that cleaning the panel as often as once or twice a week is a good idea. Cleaning your LED light panel is a great way to help it last for years to come.
When you say LED, are you referring to the newest strings of lights out there, or just the lower wattage mini lights that have been available for a long time, For someone who went through 2 of 5 semesters of Digital Electronics Tech 10 years ago, I have forgotten just about everything. I saw a video a while back that said some lights have a third wire, and that wire can be snipped out without any problem.
i have 21,000 lights most led on both types of sets its almost always the bulb. hardly ever the wires the key to keep the lights work 1. don’t pull hard on the light strands and 2. after using them put back in the boxes that came from the store. to fix one find the burned out bulb and changed it most sets come with 2 Exeter bulbs. test the set the way he said with volt tester. I got about 400 set of lights. if you put a lot of sets together end to end fuse will burn out. read the box and never roll all sets in a big ball if you do kiss most of the sets good buy I got some sets that are 25 years old and slowly getting rid of my non led lights the paint on them fad out over time led,s don’t do this. and buy them after Christmas and save up to 75% off.
Plug in the LED string. It doesn’t matter if it or the section in question lights or not. Now, examine in a darkened room or dark shade. There will be a faint (and I mean FAINT) blue glow–a tiny dot–in every good LED. Bad LED’s will have no faint blue dot of light. Let me emphasize the words ‘faint’ and ‘tiny’ again.
Reading this carefully, you’ll see the author clearly state that cutting out a socket is a measure to be taken only if nothing else works: “If all else fails, the bulb socket may be broken beyond repair.” The way he suggests is pretty good. Using crimp tool connections might be a little better, but both should be plenty safe. Adding electrical tape to hold the wire connector in place might be a good addition to this part of the instructions.
One possibility is to go down the string light-by-light and remove a bulb, test it, then put it back if it tests good. But not only is that a heck of a lot of work, it has the potential to make things much worse: When the string does not light up we cannot know that we have seated a bulb properly.
There are several ways to illuminate the pool and pool area. There can be exterior floodlights, landscaping lighting, pole lights, underwater lights and pool house lighting. What we will be reviewing in this article is common underwater lighting in concrete swimming pools. We recommend that someone experienced with these types of lights conduct any investigation and repair.
Devices are sold to help with the issue of finding the bad bulb without first removing it. One sort of device picks up the 60Hz hum from a wire which is connected to the “hot” side of the AC line. Then one can follow that hum from the plug, into and out of each successive light socket, until at some place the hum fails. Then we have a bad bulb, or a bad connection, maybe just a poorly-seated bulb. The device I got a decade or so ago was helpful, but also relatively insensitive and tricky to use.
Pull out the tail light fuse and look for cracks as well as the state of the metal filament inside. If it looks burnt or if it is not connected, or if you question the fuse at all, replace it with the correct size fuse.
You have 2 plastic clips that you attach so that the bulbs that do not light up are between the clips. When I plugged my 70 bulb string into the wall, there were 35 bulbs that didn’t light. The clips marked off this section of the light string.