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Problems With Led's When Used With Lor


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I've been using a mix of LED's and incandescent lights since 2009.  They were Walmart brand LED C9's and I love them.  Only had one string go out this year which was fixed using the LED keeper.  Now for 2012 I purchased probably 200 boxes of LED's from local Giant Eagle grocer's as well as Walgreen's.  None of these sets had a round resistor or rectifier on the string.  They were basically similar to the typical "mini" sets with replaceable bulbs.  I've not had any failures yet and I'm pleased with how well they work, but I'm noticing that they do not completly shut of.  In some instances when I have a fast "chase" some sets seem to remain on.

I have six 5-channel firesticks that were used last year.  They were Walmart brand mini 60ct LED's and have the rectifier. Last year they worked perfectly without a problem.  This year, however, they are "sticking" on.  It can be a bit annoying. 

So with this in mind... is this what the "snubbers" do?  Resolve the problem of the LED set NOT turning off?  Also, I notice that sometimes a song will come on and a certain tree comes on when it's not programmed to turn on.  It will "shimmer".  And when I look in the sequence to see if in fact I had "turned it on", the sequence shows that the channel was not even used.   I thought maybe I had the channel mixed up but that was not the answer. So I'm a bit confused.  Anyone experience this before?

I'd like to take some videos of the display, but with so many little "bugs" I don't want to capture the errors.  Most times the songs run just fine with the lights, then other times they don't work exactly right.

Any comments or suggestions? Thanks!

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Hey Clyde...the triacs used as the "switch" in the LOR controllers have to see zero volts in order to turn off.  This happens 120 times a second with a 60 hertz sine wave.  LEDs have a parasitic capacitance that acts as a very tiny "battery" and stores a voltage.  This stored voltage delays that channels line voltage reaching zero because it discharges back into the line.  A snubber provides an additional discharge path for this stored charge so that the voltage will reach zero much quicker thus allowing the channel to turn off much sooner. 

 

This might also take care of the shimmer problem you mention, although I am thinking your shimmer may be caused because your LED strings have a half-wave rectifier.

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I am seeing this problem as well this year.  I think some of my troubles are due to having the LED strings out on the end of a 100' cord!  I made up some long cords to run some bells that have LEDs on them and noticed that they were flickering and not shutting down on quick sequence actions.  They would also flicker when I run a static display and the sequence would make a change in lighting, sometimes they would flicker and sometimes not.

I used an O'scope to check and saw the transients on the lines as well as small voltages setting on them sometimes as well.

I installed snubbers on the lines and all problems have disappeared.  Everything runs crisp and snappy with no more flickers or LEDs remaining on at the wrong times.

I wish all problems were this easy to solve - HA.

 

It does seem too that as the strings "age" they can get prone to having more troubles.  Not always but I do see some strings that are beginning to act up slightly after 4 years of use.  I think that after the show season is over I will hook up some test equipment and run some testing cycles on the strings to see how they do against a new string (some of my backup stock).  I will also be able to get a baseline off the new strings to compare the operation against.

The trouble with the LEDs is that this "use" of them is pretty new and no one really has any good baseline information or testing to compare things against as well as different manufacturers are making these things without any real standard to go by so different brands will behave, age, work a little differently.

 

It would be good to find anyone who is running any tests on this stuff to get some information on things.  Of course now RGB is coming into the picture and that will bring a whole new set of problems and new methods into play as well.

 

Gets tough to keep up with changing times as running tests to accumulate data takes time.

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You can test to see if a snubber would help adding a nightlight to the channel and see if it behave. Sometimes there isn't enough load on the channel.

Thanks, I'll try this out!

 

Hey Clyde...the triacs used as the "switch" in the LOR controllers have to see zero volts in order to turn off.  This happens 120 times a second with a 60 hertz sine wave.  LEDs have a parasitic capacitance that acts as a very tiny "battery" and stores a voltage.  This stored voltage delays that channels line voltage reaching zero because it discharges back into the line.  A snubber provides an additional discharge path for this stored charge so that the voltage will reach zero much quicker thus allowing the channel to turn off much sooner. 

 

This might also take care of the shimmer problem you mention, although I am thinking your shimmer may be caused because your LED strings have a half-wave rectifier.

I am most aware that since these are the cheep LEDs, they are mostlikely the half wave versions.  Although, I do know that my warm clear LEDs are full wave. 

Keep in mind that these cheep LEDs DO NOT have a cylinder shaped rectifier anywhere on the line.  I do like the half wave because they look the best when you use the "shimmer" function on the display. 

But I want to get this straight, the LED's store the energy sent from the controller in the rectifier.  Because the rectifier is stores it, the string can stay lit?  Ok I think I understand this.

But what about the fact that strings that aren't even used in a sequence? For example I have "blue" on the trees that I just hooked up and sequenced only to 1 song.  However, they sometimes turn on (and shimmer) in songs that don't have those channels sequenced.

 

 

Yes, I have solved this same issue using snubbers.   If you don't have one, a Glad plug-in will work in a pinch.

I have an extra glade plugin :D

 

I am seeing this problem as well this year.  I think some of my troubles are due to having the LED strings out on the end of a 100' cord!  I made up some long cords to run some bells that have LEDs on them and noticed that they were flickering and not shutting down on quick sequence actions.  They would also flicker when I run a static display and the sequence would make a change in lighting, sometimes they would flicker and sometimes not.

I used an O'scope to check and saw the transients on the lines as well as small voltages setting on them sometimes as well.

I installed snubbers on the lines and all problems have disappeared.  Everything runs crisp and snappy with no more flickers or LEDs remaining on at the wrong times.

I wish all problems were this easy to solve - HA.

 

It does seem too that as the strings "age" they can get prone to having more troubles.  Not always but I do see some strings that are beginning to act up slightly after 4 years of use.  I think that after the show season is over I will hook up some test equipment and run some testing cycles on the strings to see how they do against a new string (some of my backup stock).  I will also be able to get a baseline off the new strings to compare the operation against.

The trouble with the LEDs is that this "use" of them is pretty new and no one really has any good baseline information or testing to compare things against as well as different manufacturers are making these things without any real standard to go by so different brands will behave, age, work a little differently.

 

It would be good to find anyone who is running any tests on this stuff to get some information on things.  Of course now RGB is coming into the picture and that will bring a whole new set of problems and new methods into play as well.

 

Gets tough to keep up with changing times as running tests to accumulate data takes time.

Bill, distance is not my problem in this instance.  The max length of any cord on my display is 25'.  Average length is 15'.  My controllers are set up directly behind the display's main tree line, or off to the right side of the house.   I agree that the problem could be part of an "aging" factor. 

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So, how have you guys built snubbers?  What is the most cost effective means you have found?  I'm afraid that it may be too late to do anything about it for this season.  So, I'll be planning ahead for next year. 

Long thread, but everything you need to know and parts: 

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Tim it is a long thread, and I've seen it bounced around here and their.  I would need to make a lot of those things Ugh :( 

Victor, how much am I looking at for the c9 socket vampire plugs ?  I'd hate to solder one socket into EACH CORD on the display :(
 

Currently looking for some night lights that could just be plugged into the line at the LOR unit.  Sounds like the easiest and least labor intensive solution.  Anyone know where to get 100 or so of them?  haha

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Wait, came up with an idea.  I made 9 LOR units by using the female end of extension cords as the dongles.  I still have all  the male plug connectors.  I can take a few strings of c9 lights and splice them on to the male ends then connect them to the end of the led!

Just tested out my first splice so we'll see if it works tonight!

Question, with this help my fast-blink firesticks work better?  Some of the sequences they are bouncing but never turn on the last channel because the timing of the flash is very very short.

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Another idea, but DO NOT DO THIS if you are not comfortable with soldering and/or electronics AND (another disclaimer) I am not advocating this approach for others!....solder the snubber resistor directly across MT1 and MT2 on the triac!  I am going to do this on the back side of the board.  If you do it, make sure the leads on the resistor do not touch anything else.  You might want to even consider an insulating sleeve around the exposed portion of the lead.   What value will I use?  Not sure.  After I break down my display next month, I will see what value LOR used.

 

Doing this will eliminate the need for a male plug to add the snubber. 

 

Dennis

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Ok, so tonight I made the C9 snubbers  but only put on one of them (the channel that was doing the worst).  And it's funny how all the issues I was having with the firesticks have completely stopped.  I'm serious!  It looks great... but I'm beginning to wonder if it  had something to do with the rain/damp weather?  The Trees that usually are acting crazy didn't act bad at all.  Like I said, I only used 1 snubber.

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