# LED Christmas Light Fix



## yuandrew

We'll, first, I haven't been here for a while so hi, I'm back.

Anyway, I happen to have four sets of Forever Bright Christmas Lights (2001 models) and a few nights before, I was playing with them. 
Anyway, I acted like a jerk and took all the bulbs out of one set and started putting them back in except when I was done, only half of the string would light up. I have spare Leds but the trouble I have is finding the bad connection. Well, I hope you guys can help me fix this. Anyway, on the other hand, what problems have you experienced with these lights?


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## Chris M.

The LED at the start, and the one at the end of that bad section could be reversed. The sockets there are a little larger to accomodate the extra wire needed, plus there`s resistors in`em to limit the current. The result is the fact that the bases are not polarised like the rest. It`s very likely that turning one or both of those LEDs round will correct your problem. Other than that, you`ll have to do it the old fashioned way of just checking each bulb and its contacts in turn till it flickers at you. It isn`t fun troubleshooting regular lights - and I have a lot of experience with *that* particular aspect of holiday decorating!

-

Last year I used a total of 1200 Foreverbright 2002-issue lights. Six sets of 70 blue, four 70 white, 3 gold 75s, 5 red 75s. I had major problems with the blue and white ones. I began to notice a couple of blue LEDs out after a week. Inspected more closely - the LEDs themselves had gone out, it wasn`t a bad connection shorting them. Changed them and all was well again, till I noticed more of them failing. By the end of the season over 30 blues and 20 whites had blacked out on me. LEDs aren`t supposed to do that! Apparently it was a bad batch of LEDs, and this has now been fixed in the 2003 release. I`m supposed to be getting replacements for my blue and white sets sent, but havn`t heard anything recently so it`s probably time to chase that up soon.

The 2003 models have non-removable LEDs and the same 5 year guarantee, that is how confident they are that the trouble has been fixed. It also alleviates the sort of problem you have with bad contacts or reversed LEDs. Time will tell if the offer is good and I get my warranty replacements, assuming (and hoping) that I do, I`ll be able to give more information about them and eventually their reliability this Festive Season.....

/ubbthreads/images/graemlins/rolleyes.gif


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## yuandrew

Thanks for your input! Actually, I tried reversing the LEDs at the end already. I think I might have to look for the loose LED the hard way. However, mine is a first generation one that dosen't have resistors in the sockets. The sets I have are the green-red-yellow ones with 100 leds per string.


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## The_LED_Museum

There's a non-contact Christmas light set tester you can get that you wave over each bulb, and see if the LED on it comes on. And when you go 1 bulb past the bad bulb, the LED no longer comes on. Back up 1 bulb, and check it for contact or whatever. When you put it in correctly (and the LED in it is known good), the entire section or light set should come back to life.

The trick to using one of these testers correctly is to make sure you have the light set plugged in with the correct polarity. If the tester's light comes on at both the first AND last LED of the section you're testing, unplug it, turn the plug 180°, and plug it back in. The tester should not come on at the last dark bulb in the set unless that specific bulb is bad or in backwards.

I have four bad strings of LED Christmas lights (2000 and 2001 Forever Brights), but I don't know where the tester is. So they're Forever _Darks_ until I can find that tester and see what went wrong.


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## TheBeam

Mr. Museum,

Where would one get one of these magic wands?


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## The_LED_Museum

[ QUOTE ]
*TheBeam said:*
Mr. Museum,

Where would one get one of these magic wands? 

[/ QUOTE ]
I think Radio Shack has these... let me check the website and see...BRB...
Go here to see one.
According to the page, the online catalogue is out of them, but you might find them at your local Rat Shack.

Part number is 22-106 if you can't find them yourself. Price is $6.99. I'm guessing you'd find these near the test leads and such, but I could be wrong here.


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## TheBeam

Thanks, now to dig up some $ from somewhere. I must have one of these.....I just realized I don't have a use for one, but feel like I need it anyway.


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## yuandrew

Thanks, Crag, I just remember my friend has a Fluke inductive voltage tester. I'll see if I can borrow that.


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## yuandrew

*Re:Fixed It*

All right, I went back to it last night and what I did was remove one LED from the working section and used it as a test socket. Found one bad green LED somewhere in the middle and changed it out. At first, the set still wouldn't light up but then I reversed the last LED and BAM, the nonworking section lit up.

Ok, with that done, I'll just have to wait until the day after Thanksgiving which is when I start putting up my outdoor lights.


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## The_LED_Museum

*Re:Fixed It*

I just broke down and bought another inductive tester from Rat Shack, so now I can go test those dead Forever Dark strings and see if I can find the bad lamps. Before I lose or misplace the tester (this would be the third one!), of course. /ubbthreads/images/graemlins/icon15.gif


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## KEN TYE

*Re:Fixed It*

hey craig , go to wal-mart next time to get a tester...much cheaper than the shark /ubbthreads/images/graemlins/thumbsup.gif


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## The_LED_Museum

*Re:Fixed It*

There's no Wall-Mart anywhere I can get to. /ubbthreads/images/graemlins/frown.gif But thank you for the advice in any case. /ubbthreads/images/graemlins/grin.gif

The one I got from Rat Shack is more sensitive than the one I had before, so it doesn't work as well on LED sets as had been hoped. I think I can still find bad "bulbs" with it, but it's more sensitive and lights up no matter where on the string you place it, and no matter which way you have the plug in the outlet.

I don't know where the spare "bulbs" are, so I might not fix the miscreant sets after all. /ubbthreads/images/graemlins/frown.gif


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## IzyWeird

Regarding the use of AC line detector devices to troubleshoot LED strings (like the little red guns). I have found that these are of little use with LED strings. They work fine on incandescent strings because the good bulbs are conducting and the line voltage can be detected down the string until you hit the bad lamp. But without any current LEDs do not conduct, and the detector will not help you find the bad lamp.


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