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Need ideal on failed lights


Big J Illinois

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I have a 100ct , 33ft C5 LED string. Was working good, til my wife pointed it out, saying the amber ones dies, then they all died. I jiggeled the plug and nothing. It felt warm to the touch....ideas?? I would go by the same set and put the plug cut off the new string on...the string that failed is a PITA to replace, on the second story...and gonna snow tonight What would u do?

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Is it a full wave set of LEDs  or cheaper half wave set?  If it is just a half wave set there is nothing in the plug that would cause this.  Some of the full wave sets have rectifier circuits in the plug and could be the culprit and swapping the plug end might work.  My guess is that one of the LEDs is bad and I would start with the amber one that dies first.

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I would start with the amber .....but the string is completly dead, fuses are good. As for the BS on "full wave" vs "half wave"....lolololololololol....there is no differance on location of a rectifier on the string of lights OR resistor. Manufactures place them in the male end, midway or in the female..as well as any resistor (s) . I will replace the set when weather permits, the string is old

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1 hour ago, Big J Illinois said:

As for the BS on "full wave" vs "half wave"....lolololololololol....there is no differance on location of a rectifier on the string of lights OR resistor

OK...good luck then.  You obviously have everything figured out.

 

 

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Yes, I can run a fluke meter....Was trying to quick fix the set without removing it, but looks like the set will be replaced.I gotta ask though, who came up with a "half wave" , "full wave " and "cheap walmart" lights... other then a sales ploy...  If anyone knows what a rectifier really does or what a resistor , feit,triac....pm me, I would love to chat and see who is BS and who really know electronic theory:)  I m not attacking you QBerg, but let's call  spade a spade....The stuff you said is a sales ploy-tactic and only that :)

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3 hours ago, Big J Illinois said:

The stuff you said is a sales ploy-tactic and only that

I don't understand how you can say that?

Half wave...the LEDS only have resistors in the strands and run off AC power.  Hence they are only lit "half" the time or in other words only in one "half" the AC (alternating current) cycle.  They flicker on and off at 60Hz because an LED is a diode and only will light when the current is in the correct direction.  Hence if your LEDs were half wave then you obviously have an LED that has gone bad or a resistor....there are no diodes in the plug or inline and changing the plug on your strand of LEDs will do nothing to remedy your problem if the fuses in it are good.

Full wave...lets just call them DC LED strands as there is a rectifier circuit inline or in the plug that converts your household AC power to DC (direct current).  This allows the LEDS to remain illuminated 100% of the time.  Or you can build a rectifier dongle (I have about 60+ on my LED strands) and put it on your half wave LEDs and they will stop flickering at 60 Hz and appear to be brighter since they are staying on 100% of the time.  Generally people only notice the flicker in AC LED (half wave) strands if the lights are moving. 

20161204_065023[1].jpg

Not too deep in electronic theory as it is no more complex than running a LED off simple AC vs DC.  Are they different?...absolutely!  Sales ploy?...In your opinion yes, but I say they are not.  Rectified LED strands have more electronic components and eliminate the 60Hz flicker.  They cost more...but I achieve the same thing for less than $1 with a rectifier dongle.....much cheaper than rectified LED strands.

Now if you really want an idea how to test that malfunctioning strand...take a jumper wire and two safety pins, bypass that amber LED and see if the rest of the strand lights.  Bypassing only 1 LED in the strand will not overstress the rest.  If it is just that bad LED take two quick splice connectors and bypass it this season.  Then repair it for next year.  Are the LEDs in removable sockets?  Pull the one prior and after a resistor blob and check the resistance between them to see if you have a bad resistor.  I have found this only partially successful as the resistors usually check fine with the small load of my mulitmeter.

To test LED strands, check out the Planet Christmas Magazine on building a tester. http://planetchristmas.com/Magazine/July2012/index.html#/28/  It is just an 12-18V wall wart and two "bed of nails" alligator clips.  Since it is AC you don't have to worry about polarity when checking the LEDs.  Very useful in tracking down a bad resistor (which I have replaced a couple in my Walmart LEDs), bad LED (replaced many of those in 2 years) or a bad socket in replaceable LED strands.

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4 hours ago, qberg said:

I don't understand how you can say that?

Half wave...the LEDS only have resistors in the strands and run off AC power.  Hence they are only lit "half" the time or in other words only in one "half" the AC (alternating current) cycle.  They flicker on and off at 60Hz because an LED is a diode and only will light when the current is in the correct direction.  Hence if your LEDs were half wave then you obviously have an LED that has gone bad or a resistor....there are no diodes in the plug or inline and changing the plug on your strand of LEDs will do nothing to remedy your problem if the fuses in it are good.

Full wave...lets just call them DC LED strands as there is a rectifier circuit inline or in the plug that converts your household AC power to DC (direct current).  This allows the LEDS to remain illuminated 100% of the time.  Or you can build a rectifier dongle (I have about 60+ on my LED strands) and put it on your half wave LEDs and they will stop flickering at 60 Hz and appear to be brighter since they are staying on 100% of the time.  Generally people only notice the flicker in AC LED (half wave) strands if the lights are moving. 

20161204_065023[1].jpg

Not too deep in electronic theory as it is no more complex than running a LED off simple AC vs DC.  Are they different?...absolutely!  Sales ploy?...In your opinion yes, but I say they are not.  Rectified LED strands have more electronic components and eliminate the 60Hz flicker.  They cost more...but I achieve the same thing for less than $1 with a rectifier dongle.....much cheaper than rectified LED strands.

Now if you really want an idea how to test that malfunctioning strand...take a jumper wire and two safety pins, bypass that amber LED and see if the rest of the strand lights.  Bypassing only 1 LED in the strand will not overstress the rest.  If it is just that bad LED take two quick splice connectors and bypass it this season.  Then repair it for next year.  Are the LEDs in removable sockets?  Pull the one prior and after a resistor blob and check the resistance between them to see if you have a bad resistor.  I have found this only partially successful as the resistors usually check fine with the small load of my mulitmeter.

To test LED strands, check out the Planet Christmas Magazine on building a tester. http://planetchristmas.com/Magazine/July2012/index.html#/28/  It is just an 12-18V wall wart and two "bed of nails" alligator clips.  Since it is AC you don't have to worry about polarity when checking the LEDs.  Very useful in tracking down a bad resistor (which I have replaced a couple in my Walmart LEDs), bad LED (replaced many of those in 2 years) or a bad socket in replaceable LED strands.

pm sent

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5 hours ago, neonexpresso said:

do you have a schematic or anything for that rectifier dongle?

As far as wiring up the dongle?  Just solder your AC input from the male plug to the two middle pins and solder your female plug to the pos and neg pins then waterproof it.  I cover it and the soldered tab with hot glue and slip the heat shrink tube over it.  Then hit it with the heat gun and the excess hot glue squeezes out.  I keep a whole box of old light string plugs.  The benefit is they are fused plugs.  When you plug in your LED strand it will either work or not...if not just reverse the plug and it will work.  I know Walmarts red, green, blue and pure white 100 count strands are all wired on the same side so you don't have to cut strands and resolder them in the middle.  The 50 count warm white have been all wired on both sides of the AC curve so only half the strand will light depending on the direction of the plug.  Just cut, swap and resolder the point where there are only 2 wires between LEDs and they will be set.  It won't hurt anything plugging the strand in backwards.  Here is a spec sheet for the 8A ones I picked up this year.  I think my original ones were either 3-5A....either way that is a lot of LEDs to run end to end off a single dongle.

http://www.vishay.com/docs/88658/kbu8.pdf

Here are the 8A ones on eBay:

http://www.ebay.com/itm/20-pcs-KBU8G-E4-51-Vishay-400V-8A-Bridge-Rectifier-Diode-KBU-4-Pin-Case-/222163579571?hash=item33b9fb32b3:g:O~4AAOSwG-1WyzYN

Switching them to DC will make them brighter, however, I have tried multiple C9 LEDs and even though they are brighter, the signle LED C9 design is not just bright enough for my taste.

 

half wave.JPG

full wave.JPG

rectified.JPG

I stand corrected on stating the Full-wave rectified LEDs are on 100%...as can be seen in the diagram they are not.  But, they are on twice as much as half wave and do eliminate the 60Hz flicker seen in half wave LEDs.

 

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Does this dongle prevent them from burning or even make them last longer? With what we do with animated displays, I have sets burning left and right.

Right now, I try to minimize the amount of power going to them by programming my boxes to run at 50% of actual power. So, instead of running at 110v, they are at maybe 60v or so.

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9 hours ago, BigDPS said:

I have sets burning left and right.

You have a lot of LED sets burning out?  and you are running them at 50%?  I run all my stuff at 100% through the boxes and have never had an issue.  Did you test the LEDs to find out which LEDs are always burning out?

As far as lasting longer by running them with DC, you are going to get 2 differing answers on this one.  First answer is they are not going to last as long because you are running them constantly on when they were designed to be flickering off 50% of the time with AC power.  Logic says that if they burn brighter they can't last as long.  I don't subscribe to that answer...you are running them at the exact same voltage.  They appear brighter because you are not turning them off and on 60 times a second.  If you were concerned you could pull down the max voltage in your boxes to make them appear the same brightness.  IF anything, I would suspect the resistors will fail sooner as you are running them near 100% and they will generate more heat.  I have seen and replaced a resistor in my cheap LED strands and dissected one from an expensive rectified set that failed....they were the same, so I don't think we are killing Walmart LED strand resistors with the DC current either.      

Which leads to the second answer....they will last longer because you are not barraging the last LED in the series with blocking the reversed current 60 times a second.  Folks have stated that when the LED strands go out, try changing the first or last LED in the section first as that is the one that usually goes out first.  Even though all the LEDs are a diode that will block reverse current, only the last one in the series ever has to.  The reverse current never makes it farther than that one.  That is why I asked if you knew which LED was always burning out with your problem.  Chances are it is the last one in the section (could be the first or last LED because you don't know which way they are wired for current flow).  If you pull a LED you can tell which way the current flows.  Current flows from the Anode (long wire on LED...pos) to the Cathode (short wire on LED...neg).  The LED does two things...emit light and act as a diode.  By running them in a DC environment they never have to act as a diode, they just emit light.     

That is my two cents on the question.  Big J Illinois...you have more experience in electronics than I do, what is your opinion? 

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Burnt sets= no good.. as for my opinion, I would check the wiring ,in terms of where the power originates from...outlet, cord, all the way back to the main lug of the service panel. I have tightened my main(s) and the neutral lug, and all circuit breakers. House was built in 02, applied oxiaway (what I call it lolol) and noticed a differance in how things react around the house. It is overlooked, but overtime, these "little" things need attention.   Start at the base of the problem, rather then the furthest thing you never would think of.FYI Deoxit is the brand I use. And lastley, is the power that feeds your controllers, upto par? What guage wire feeds the circuit? Go oversized, you'll be happy you did:) As for the electronics....it's kind of like 2 way radios (off the subject for a sec) , any 2 way radio you use, if the power is dirty, unclean, who cares if the antenna is good....it stems from the beginning....the power source (sine?):):)

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The first thing I thought of was the quality of the electricity to the home as well.  Is it possible you could have power surges that are damaging the lights?  The Rectifier Dongle will not stabilize anything like that.  If your AC fluctuates 100-140V then the rectified DC output will just fluctuate along as well.

 

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I am wondering if DPS has underground,near a failing transformer, or loose wiring also.I would start there . Hey DPS, have you takin any power readings, through out the day? Or does this occur when other neighbors turn on there diaplays? OR you trying to use 40 amps on a 60 or 100 amp service?

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All the Half wave I used to have were just that, they used a half wave rectifier because they are cheaper, (two less diodes). They did not rely on the last LED in the chain to keep current from flowing the opposite direction.  (check valve if you are a mechanical type).

 

(I also have an electrical background, and made my living doing such for years.)

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13 hours ago, prevue12 said:

All the Half wave I used to have were just that, they used a half wave rectifier because they are cheaper, (two less diodes).

What brand were those? 

I know for a fact the Holiday Time from Walmart have no diodes.  In fact the pure white, red, green and blue 100 count strands don't even use resistors...they vary the LED count in a section to adjust.  Pure White 50 count don't either.  All of the Holiday Time Warm White strands I have used utilize resistors.  I have not messed with/modified other brands.

You make a good point though!  Know what you have before you start modifying!  They are not all the same and when you compare prices....you get what you pay for.

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Sorry for the late reply, been extra busy.

The strings that burn always seem to be the blue ones. On multicolored, I notice they are the white ones that usually burn. I do have a LED Keeper tool and like some mentioned, most o f the time, it is the LED right before or after the one that has 3 wires coming out of it. On some of my strings there might be 1 or 2 not glowing but the string still works. Having said that, most of the times the string will just stop. Then it is time for me to try to find which one is burnt. And don't get started with the stupid replaceable LED type. Here in Lincoln New Brunswick, the temperature can swing any which way. Warm and rainy in the afternoon only to have a killer freeze at night. Then, the water becomes ice and pushes any contact from the light and no show. Not nice going out with a hair dryer trying to warm the right light.

 

True anecdote: One year, some moron told me that my display was not as impressive as the ones he had seen on TLC during their light competition. It was pouring rain and freezing rain. I told him "Buddy, let's see how many are in t-shirts right now. Of course it was only him and I and then I said "Go back to your f'n TV show and notice how many of them have no snow, how many people are in t-shirts and so on. If you don't like it, I'm not paying you to look at it so get the Fire truck out of my life. " He never came back. Good riddance.

Hard to run a show where the weather dictates how it will run. I even had a box catch fire one year. We had rain then it froze then thawed again. It created condensation and somehow, short circuited and hell broke loose. Oh the fun people that come to see the display and what they miss running in the background.:huh:

EDIT: I have checked power and it is clean and no brownouts that I can see.

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