How To Repair Outdoor Led Light Strings

LED lamp strings tin be repaired. Information technology can be equally simple as replacing one failed bulb but can be more than complex. Oftentimes information technology is non easy.

Early preventative maintenance, a dab of grease into each socket when new will help prevent corrosion caused failures. These strings could concluding much longer if the manufacturers did this for the states at minimal cost. Only you can do it yourself. Keep these strings running and out of the landfill.

**NEW** Mar 12 2022 Please see the Addendum for some updates and new pictures.

Don't LED lights last forever?

Apparently not, particularly when used outside.

Winter is very damp here in Canada. Water gets into everything, including supposedly sealed outdoor lighting. The h2o causes the LED leads to corrode and neglect. This corrosion failure of LEDs due to h2o can be completely and easily stopped with a dab of grease, if defenseless early.

Failed bulbs that you can meet should be replaced promptly since they crusade the residual of the string to be nether more stress and may lead to more failures. I had the kind of failed bulb that prevented the whole string from lighting. Both kinds of failure tin can occur.

Like almost of us, I bought into the LED low power and eco friendly affair a couple of years ago. I threw out the former filament bulb outdoor Christmas lights and bought new GE branded outdoor LED cord lights.

Yesterday, while getting set up to put upward the Christmas lights, I found that ii out of eight strings did not piece of work. Each has 25 LEDs. I spent part of the twenty-four hour period exploring why those had failed and putting up the residual. Fortunately I had tried them before putting them upwards!

(click any picture show to enlarge it)

My GE strings are supposed to be repairable. They come with instructions (the full re-create, a pdf) and spare LEDs.

The worst part about my two failed strings was that none of the bulbs lit upwards. Not i or two bulbs that weren't on while the remainder worked. The failed seedling could not be seen since information technology kept all the others from lighting. This meant that each bulb had to exist pulled and a working bulb inserted (according to the manufacturer's instructions).

I idea that we had abandoned series wired calorie-free strings dorsum in the 60s? Series wiring is back with LED lights!

I tin can call up my dad back in the day proudly showing off a new parallel wired string, with which 1 failed bulb would not darken the whole string. He had spent many a fourth dimension finding a failed seedling in a expressionless cord so he knew the reward of parallel wiring. From so until now, the advent of LED lighting, most of our filament bulb lighting strings were wired in parallel.

Series wiring is back with LED lights! It turns out that there is a technical reason why LEDs demand to be wired in series and this volition be discussed below. Since they are wired in series, I need to check every LED bulb if none of the string lights. Any i of the LEDs could be open excursion.

In that location are 25 LEDs in each string and so that is 25 decorative caps to pull off and and so 25 LEDs to pull out. Some of the caps come off easily, others exercise not. I found that a driblet of WD40 helped gratis some of the stubborn caps. I dripped the lubricant onto the articulation betwixt the cap and the socket.

Some of the caps bankrupt when I pulled them off, usually a function of the sealing ring was left in the socket. I dug out the debris from the socket and discarded those caps and replaced them with spares from the bit strings. The caps are keyed and only fit on one way. Why they did this I am not sure.

I admired the kickoff form molded parts that fabricated up the socket assembly including the LED holder, the cap and the base. At that place was no wink and the parts fit together very exactly and securely with a snap. With ideal plastic that did not weather or change dimensions or properties with UV and temperature, these would exist really overnice parts. After a couple years outside, some are harder to go apart than others.

Pulling out the LEDs was sometimes problematic. I used my fingernails inserted in a small groove between the LED and socket and just pulled. Here also, a bit of lubrication from the dielectric grease helped with subsequent removals.

Throughout all this pulling on the socket, I tried not to pull on the wires. They seem securely crimped into the terminals but I thought it all-time not to pull too difficult on them. The terminals are a potential point of failure so while the LED was out of the socket I took a expect at the joint with the wires and the condition of the terminals before dabbing the grease and re-inserting the bulb. The inner (insert) portion of the socket tin can be removed and that will be described below. I found information technology was desirable to remove the insert on those where corrosion was seen in the socket.

Information technology'southward virtually RUST

The crusade of my failures was common corrosion. Each LED is itself encased in articulate plastic only the metal leads that form it's connection with the socket are made of iron or steel and these leads rust if exposed to water and oxygen. The socket weatherproofing can be improved with a dab of dielectric grease to prevent the oxygen and water from reaching the point where two dissimilar metals touch: the LED lead (iron) and the socket contact (some other metal). Why wouldn't the manufacturer practice that?

If I doubted that the LED leads were ferrous, hither is a picture of the rusted ones stuck to a small-scale magnet. You tin meet a cleaved off LED lead in the foreground.

I have opened all the bulbs on three of my LED strings and so far. Ane that I scrapped had a high percentage of failed bulbs 8 out of the 25. Another that I did not flake had merely one of these trouble bulbs. All of these bulbs failed because the LED leads rusted. Some of the LED leads had fallen off or rusted completely through.

Probably millions of these string lights will end up in the landfill over the side by side few years considering people volition surrender on them. Hopefully you tin can utilise some of these ideas to assist yous to locate the problems with your own and proceed them going for a few more years.

Understanding how LED string lights work

You practise not have to cut the LED string autonomously and unwind it equally I did here but it helped my agreement of how the thing was put together and I am going to use this motion picture to explain what I found.

Parallel wired light strings have two wires down the length of the cord and each lamp is wired betwixt the pair of wires. These LED strings have three wires down the length. It is a little difficult to run into what is going on unless you do what I did with a string that was damaged beyond repair. I separated the string into two parts past clipping at only i point. I could then unwind the cord into it's two sections every bit revealed in the motion picture to a higher place.

This is a schematic of my LED string. I clipped the wire at the bottom of the canister. The center portion, the string of LEDs, tin then exist separated from what I've chosen the extension cord portion. You can see in the schematic, the wires across the very pinnacle and bottom connect the plug at one end to the socket at the other. The series string of LEDs is inter-wound, merely is split from, the extension string except at the very ends where the LED string and the canister join the excursion, across the two hot leads.

Then you lot can see the LEDs are all in a string and that if whatsoever of the LEDs fails open, the current flow in the string will exist interrupted and the entire string will be dark. Different filament bulbs which rarely neglect shorted LEDs can fail in this style. No lite is produced nevertheless current continues to flow through the LED. Information technology is thus easy to see which LED failed since it will exist the dark 1.

It is interesting that in the GE instructions, they seem to presume that the LEDs volition fail short and you should look for dark ones and replace them. This was not my experience. All of my failures were failed open up circuit, due to rust.

I sacrificed 2 of the canisters to dissection for the cause of this project. You can see that my method improved after I learned to cut through the encompass sheath at the joints of the inner cylinder. There are two 2000 ohm 1 watt resistors and a diode wired in series on a three section frame. Kind of a clever thing. No signs of water ingress with either i, dissimilar with almost 10-20% of the lamp sockets. Simply I had to expect to see what was in here.

I'd like to point out the excellent writing of Terry Ritter "LED Christmas Lights and How to Fix Them". Terry has been down this road and he writes almost how LED strings work and what he learned with strings made by Philips. These I take from GE seem very similar.

Terry describes that the LEDs are bundled in series strings because they practice not tolerate high voltage well. The voltage that comes from a wall plug (120VAC in North America) is loftier voltage to an LED which normally operates from a few volts - three.1 volts in the example of my white LEDs. By stacking 25 of them in a string, each LED drops 3.ane volts then the total voltage drop across the LED string is 77.v volts. The resistors in the canister are used to drib the residue (120 - 77.5 = 42.five volts).

Interestingly, if LEDs fail short, they increase the voltage drib on all the other components in the series circuit so the resistors get hotter and all the other LEDs pass more current. So you tin see why GE tells us to "replace failed bulbs promptly" because the whole string goes into overdrive way if LEDs fail shorted. If they neglect open, the whole string goes dark and no current flows.

Terry establish that the Philips LED string contains a pocket-size fuse in the plug finish. If the fuse blew, the string would not light. Do I take a fuse? No mention of a fuse in the GE pamphlet. I attempted to find such a fuse and went and so far as to destroy the stacking plug cease of one of my rejected strings. I recollect I can say with authority that at that place is no fuse in the GE unit. Maybe where Terry is, they need to take a fuse? You should eliminate that possibility, that you have a fuse. Sometimes the "fuse" is thermal and permanently cuts the excursion. Something like that would exist in the canister, with the resistors.

Terry talks about failed LEDs being dark and easy to spot, and so obviously he saw lots of the failed curt type. Non hither. Terry wrote in 2007 then perhaps the LEDs are different now. He uses LEDs of dissimilar colors whereas mine are all white.

Terry also mulls the lack of a blocking diode in the Philips string and suggests that manufacturers add a blocking diode to better protect the LEDs from opposite transient voltages and it seems that GE listened to his advice and added such a contrary blocking diode in the canister.

Finally, Terry points out that running LEDs from AC ways that the LEDs are merely on for a part of the fourth dimension leading to a flicking effect.

I attached a current meter to one of the wires in the GE LED string and displayed the results on an oscilloscope to show what Terry is describing.

The green oscilloscope trace shows that most of the time (the flat role of the trace), the LED is OFF and for about 1/three of the time, 60 times a second, the LED string conducts hard, upward to about 44 mA maximum then goes off once again. 44mA is a lot of current for an LED of this size which would normally run at between 10-20 mA current if it was continuous or DC electric current. I suspect that the string would appear much brighter however use the same toll of electricity if the string was operated from DC rather than Ac.

I will await at that possibility in a future article.

Fixing the LED sockets

The main failure mechanism I had to deal with was rust in the sockets (rust is an insulator) and deteriorated LED leads.

The LEDs with deteriorated leads (whatever sign of rust at all) were discarded and replaced. Fortunately GE had supplied a number of spare bulbs (nearly six) with each string. Working ones from the scrapped strings provided more spare bulbs and caps.

The sockets were cleaned in the following fashion. I found that it was possible to separate the sockets into ii parts by pushing out the inner section with a small blunt tool. You can lay the socket with its open face flat on a surface and push hard on the center, between the wires, to free it up. Then if you choice the socket up and push, the center portion should just come correct out.

This picture is a bit ugly with the socket guts covered with Vaseline, the dielectric grease I had handy. This socket was especially badly coated with rust and the LED leads had completely disintegrated so it is the i I wanted to show yous.

Information technology is interesting that in whatsoever galvanic pair of metals, it is one metallic that corrodes and the other is fine (more nearly galvanic corrosion). In the case of these sockets, the LED lead suffers merely the contacts are ok except that they are coated with rust. With the socket disassembled it is very like shooting fish in a barrel to become at the top edge of the connector to clean it up. This one has been together for a while potted in Vaseline which seems to exist lifting the rust residue which is fine, both the Vaseline and the rust are insulators. The point of the Vaseline is to keep h2o and oxygen away from the LED lead and the place information technology touches the conductor in the socket. Y'all tin can run into the bright metal edge on the socket conductor where I have scrubbed it with a small screwdriver to clean up the edge. It is only these top edges that touch the LED leads, you don't need to worry about cleaning up anything else. To re-seat the contacts, only push them back into the socket. They volition click into place. The Vaseline helps to seal the articulation where the wires enter the socket also.

Finally, I ran a bead of Vaseline around the base of the cap earlier inserting it into the socket. This improves the lubrication so the cap is hopefully easier to remove adjacent time and the film of Vaseline would help to seal the articulation between the cap and the socket, helping to go along out the water.

Hopefully these lights will continue to give good service for years to come.

Your comments are welcome. Thank you for your interest and skilful luck with your LED light strings.

George Plhak
Lion's Head, Ontario, Canada

**NEW** Mar 12 2022 Please see the Annex for some updates and new pictures.