Now this is WEIRD!

[chuckd]

I've been dorking around with the system since my other post. I had noticed random channel flashing when certain parts of the sequence were running, and no flashing when other parts were running.

SO, I went into the Hardware Utility to see if I could make something happen.

What I found out was, when I do a FADE, nearby channels flicker, even on nearby controller boxes. For example, I can FADE ON channel 1 of box number 5 (nothing else on anywhere), and I noticed all the channels on boxes 2 through about 9 flicker during the fade! Doesn't matter if I fade up or down.

THEN, I just tried to turn on the same channel to certain intensities. First off, 50%. Boxes 2 through 9 flicker all over the place!!!

If I set any intensity on channel 1 of box 5 anywhere from 18% to 84%, all the other nearby channels go nuts. Below 18% or above 84%, everything else is just fine.

I tried this on a channel in the middle of my leaping arches. Everything nearby flickers IF the intensity is between 18 and 84%.

What the heck is going on?

Side note... all my controller boxes are currently laying on the ground. It's not particularly wet or anything. Not sure if this is even an issue.

Please don't say 'Don't use fades', that would be a TON of programming rework at this point, and my 'Go Live' date is this Friday.

I'm open to any suggestions, and thanks again for any help.

Chuck

[chuckd]

One more thing: I'm also using the weird CDI C6 LED's this year with the removable bulbs (Aaargh!)

Chuck

[Fred]

chuckd, I hate to say this, but I think you may have already identified the problem. Many of the 2008 CDI/Innovalite C6 strings use a voltage doubler circuit that spews an incredible amout of electrical noise when faded or dimmed. From what I've seen, this noise can get coupled into other channels, making them flicker. Worse yet, many of these strings tend to die when subjected to fading or dimming.

Sadly, I'm not sure there's much you can do about it. I was forced to spend hours rewriting my sequences in an attempt to mask this problem. It's a sad situation.

[Rafter Bar R]

What I do not understand is to why LED manufacturers are not marking their strings as "dimmable" or "non dimmable". Don't the designers for these companies read ANY discussion forums regarding on how people are using these lights?

What seems to be the problem is not a voltage doubler, is that some LED products use capacitors in them to smooth out the flicker. The single C-7 and C-9 LED replacements for 120 V AC light strings use a capacitor inside the bulb assembly. Some may even use a voltage regulating device. It's LED products that use these components that tend to have problems with dimming and fades. Hope this helps somewhat.

[garyfunk]

This has also been reported here: http://lightorama.mywowbb.com/forum76/17569.html

[Fred]

lonewolvie wrote:

...What seems to be the problem is not a voltage doubler, is that some LED products use capacitors in them to smooth out the flicker...

lonewolvie, I believe the noise problem chuckd has been experiencing is indeed likely caused by the voltage doubler circuit. I know for a fact that the electrical noise I have witnessed using the 2008 Innovalite 100 count C6 strings has been caused by the voltage doubler when the strings are dimmed. Different colors (and thus, different forward voltage drops) spew noise at different fade levels. I've watched it on an oscilloscope. (Of course, classic voltage doublers do indeed use capacitors. They have to.)

If I was going to design an LED string from scratch, I would actually consider using a capacitor to reduce ripple in the rectified AC. But, it would have to be properly sized (and/or bled with a resistor) to prevent any sluggish turn-on/turn-off times. As a matter of fact, I think the 2007 Innovalite strings used a capacitor for just that purpose with no ill effect. But, I'd never, ever use a voltage doubler for strings intended to be dimmed. There are other, much better ways of powering high count LED strings.

You are correct that some high intensity LED products use voltage regulating devices. (Well,... technically, they use a "constant current source" circuit.) These devices are definitely not dimmable.

However, I completely agree with you that all we LOR users require is the simple "NON-DIMMABLE" warning. Such a warning would have saved me a fist full of dollars and incredible amounts of time and frustration.

[heystew]

Please see the original thread on this topic for my test results using a snubber.. and new questions
http://lightorama.mywowbb.com/forum76/17569.html

[Paul Roberson]

chuckd wrote:

One more thing: I'm also using the weird CDI C6 LED's this year with the removable bulbs (Aaargh!)

Chuck

Unhook the CDI c6 strings from box 5 channel 1 (one that you said you did a fade on) and plug in incandesent strings to that channel. Now do a fade on that channel again and see if there is still the flicker on other channels.

[chuckd]

Yep, put in my old Diogen lights, and no problem.


I also got out my oscilloscope, and saw horrible kick-back noise when they're dimmed... All the way back into the power lines! That's why all the nearby lights go nuts.

It's the CDI LED's, not LOR.

[heystew]

Is it noise that might be taken care of by a ferrite bead installed on each channel?

[FBW4]

A cap across it to filter it out?

[NWSanta]

Apparently it appears to be an LED problem. CDI sold a bunch of LEDs that were problematic, if you purchased LEDs this year from Creative Displays and haven't received a letter from them, call Paul or email him and see if you do in fact have the bad LEDs.

I ran some tests across my Arches last night and all of a sudden a portion of one of my strands went out I guess I have to de wrap and re wrap that section, good thing I kept some spares.
-Evan

[chuckd]

Evan,

If you haven't done it, you MUST take out all fades from your sequences NOW!

Otherwise, you'll continue to get failures at an alarming rate. As is, I'm getting 4 strand failures a day WITHOUT doing fades. It was much, much worse when I was fading.

Sorry,

Chuck

[NWSanta]

Hey Chuck,

I'm a little curious about my LEDs. Reason I said that is Only ended up buying 3000 Green C6 LEDs on the Pre-buy purchase but, at that moment in time Paul had them in stock and shipped them out. I wonder if I actually have the bad ones or just happen to have a bad strand.

They look quite similar to the ones from Early 2007 that I purchased.
It's raining now and I don't feel like going out in the rain to play.
Thanks for the headsup though; I'll keep an eye on my lights. I'd really be upset if these lights fail even before the show get's off the ground cause they look amazing.

The really sucky part is that I can't find Green LEDs here in Canada anywhere. If I need more that is.

I guess if worse comes to worse and they start dropping like flies I'll just de wrap one arch go from 4 to 3 arches and then send them back to CDI in the New Year.

-Evan

[Paul Roberson]

NWSanta wrote:

Hey Chuck,

I'm a little curious about my LEDs. Reason I said that is Only ended up buying 3000 Green C6 LEDs on the Pre-buy purchase but, at that moment in time Paul had them in stock and shipped them out.
-Evan

If he shipped them out when you ordered them during the pre-buy, then you probably got lucky enough to get the 07 lights.

Most 08 pre-buy lights did not ship till late Aug. or Sept. If you got them earlier than this you probably did not get the....hmmm...lets say stuff we did.

[NWSanta]

Hey Paul,

I'm hoping that I missed the boat on the bad ones and I just have a bad section. They seem to be ok so far... Mine aren't individually replaceable either and they are 50 ct not 100s of the C6.

Hope they get me through the season.
Cheers
Evan

PS -- thanks for all the replies it's good to know people out there are listening...

[Paul Roberson]

NWSanta wrote:

Hey Paul,

I'm hoping that I missed the boat on the bad ones

LOL Yeah you probably missed the boat. Most of us had to wait on the boat...LOL

Sounds like your display will probably not suffer from bad lights.