christmas lights

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stew

Senior Member
Anyone out there ever figure out how to test and repair these darn little buggers. It seems you must have to feed and water them while in storage otherwise they seem to expire on thier own while in the box!!! Seems like every year you remove working strands and lo and behold a year later either half the strand works or not at !!. Very frustrating and I cant seem to figure out why they dont work. You would think something that looks this simple wouldnt baffle an old sparkie but they do!!!!
 

Twoskinsoneman

Senior Member
Location
West Virginia, USA NEC: 2020
Occupation
Facility Senior Electrician
I'm convinced these guys are meant to be one-use-disposables. It's the problem with having lights wired in series... they suck.
I will check the little fuse built into the plug but beyond that I don't waste my time. Just spend the couple bucks to replace the string.
 

Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
Anyone out there ever figure out how to test and repair these darn little buggers. It seems you must have to feed and water them while in storage otherwise they seem to expire on thier own while in the box!!! Seems like every year you remove working strands and lo and behold a year later either half the strand works or not at !!. Very frustrating and I cant seem to figure out why they dont work. You would think something that looks this simple wouldnt baffle an old sparkie but they do!!!!

The bigest problem is that people take a known good bulb and use it to test the string until it works. It usually doesn't work and the string gets thrown away.
Understanding how many of the strings made today work is key to understanding how to fix them. Most of your strings are wired in series in 50 light strings. The 100 light strings have 2 50 light series wired strings. most of the newer lights have a shunt that is supposed to complete the circuit when a bulb burns out so the rest of the lights remain lit. The problem with this is that in series wiring, when you decrease to number of lights and replace them with low resistance shunts, the voltage increases. When two lights burn out, the voltage goes even higher until every light on the string blows out because the bulbs are rated for 2.4 volts and the series voltage is too high. One can only hope that a shunt has failed to work and saved most of the bulbs. Look at the bulbs first to see if they all are black from blowing out.

With all that, I have found that the easiest and quickest way to repair these is to use 2 strings of lights. Have 1 string plugged in and burning. Take the nonworking string and plug it in. Start at one end and remove one bulb from the nonworking string and install it in the working string to make sure the bulb actually lights. If it does, reinstall it in the nonworking string, and repeat until the string works. By installing the bulb from the nonworking string into a working string, you are making sure that the bulb is in fact, a working bulb. Using a VOM to ring out the bulbs really isnt an option because of the shunts. Besides, the wires are too little for most sparkies fingers trying to hold the bulb, the meter, and both probes. Then there is the issue of old eyes and the reading glasses...:lol:
 

Twoskinsoneman

Senior Member
Location
West Virginia, USA NEC: 2020
Occupation
Facility Senior Electrician
use 2 strings of lights. Have 1 string plugged in and burning. Take the nonworking string and plug it in. Start at one end and remove one bulb from the nonworking string and install it in the working string to make sure the bulb actually lights. If it does, reinstall it in the nonworking string, and repeat until the string works. By installing the bulb from the nonworking string into a working string, you are making sure that the bulb is in fact, a working bulb.

Man.... I applaud your patients. That is just more than $2.69 worth of work to me :)
 

eric9822

Senior Member
Location
Camarillo, CA
Occupation
Electrical and Instrumentation Tech
I got one of these at Home Depot recently after talking to a guy who likes to decorate his house in a manner worthy of YouTube videos. I was pretty skeptical and I have not tried it yet but he swears up and down it works.

http://lightkeeperpro.com/
 

Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
I got one of these at Home Depot recently after talking to a guy who likes to decorate his house in a manner worthy of YouTube videos. I was pretty skeptical and I have not tried it yet but he swears up and down it works.

http://lightkeeperpro.com/

This device will make a defective shunt work. Once a couple of shunts are working though, the voltage will get too high, then all the bulbs go...http://www.lightkeeperpro.com/How-It-Works/how-the-lightkeeper-pro-works
 

rich000

Senior Member
I have LED lightstrings now for about 5 years. They seem to hold up better. I only have 1 half of a string out that I am assuming is a fuse. I just have not gone out to troubleshoot yet.
 

Twoskinsoneman

Senior Member
Location
West Virginia, USA NEC: 2020
Occupation
Facility Senior Electrician

qcroanoke

Sometimes I don't know if I'm the boxer or the bag
Location
Roanoke, VA.
Occupation
Sorta retired........
With all that, I have found that the easiest and quickest way to repair these is to use 2 strings of lights. Have 1 string plugged in and burning. Take the nonworking string and plug it in. Start at one end and remove one bulb from the nonworking string and install it in the working string to make sure the bulb actually lights. If it does, reinstall it in the nonworking string, and repeat until the string works. By installing the bulb from the nonworking string into a working string, you are making sure that the bulb is in fact, a working bulb. Using a VOM to ring out the bulbs really isnt an option because of the shunts. Besides, the wires are too little for most sparkies fingers trying to hold the bulb, the meter, and both probes. Then there is the issue of old eyes and the reading glasses...:lol:

That is exactly how I do it!
I use icicle lights and you don't replace them for $2.69. However I keep my eyes open for them on clearance. When I find them at a good price I just buy enough to replace all that I have and toss the old ones. Maybe keep a string just for spare bulbs.
 

rich000

Senior Member
Here's a tip for storage for you all. Roll up the lights like a ball of yarn. Seems like it would not work, but it prevents the light sets from tangling with each other. Then when you take them out, you just hold one end and toss the roll or unroll as you go.

This does not work for icicle lights though. I used to just put each set in a plastic grocery bag.
 

kwired

Electron manager
Location
NE Nebraska
Here's a tip for storage for you all. Roll up the lights like a ball of yarn. Seems like it would not work, but it prevents the light sets from tangling with each other. Then when you take them out, you just hold one end and toss the roll or unroll as you go.

This does not work for icicle lights though. I used to just put each set in a plastic grocery bag.

I have wound them up on empty wire reels - get your rack out when you want to install them and pull off the reel.

Sell your empty reels to the guys that have huge displays.
 

PURE

Member
Location
columbus, ohio
VOLTAGE TESTER

VOLTAGE TESTER

Plug your set of lights into a cord, something with multiple openings. Now take your voltage tester and stab one tip into the same outlet source.
Start going up you light string stabbing through the insulation, you will either get voltage or continuity depending on what side your first one is plugged into.
When you pass the bad lamp you will get nothing, now you have found the bad connection, be it shunt or lamp connection.
(You can save time and skip 5 or 10 lamps at a time)
 

kwired

Electron manager
Location
NE Nebraska
Maybe to limit dangerous voltages at the light sockets?

Normal voltage across the lamp will be low, open circuit voltage will still be 120 volts, voltage to ground will depend on how many lamps are in series between the one you are looking at and the beginning or end of the series.
 

realolman

Senior Member
Normal voltage across the lamp will be low, open circuit voltage will still be 120 volts, voltage to ground will depend on how many lamps are in series between the one you are looking at and the beginning or end of the series.

Now, that brings up kind of a question in my feeble mind.

I think you and two skins are both correct. So with the circuit open, but with the series resistance of yourself and the remaining lamps, just what is the voltage to which you are exposed? Its line voltage when it's open , but it's something else when you touch it....

and what kind of current would likely be available?
 
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