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MR16s will not dim with new LOR DC Board


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I was able to get about 80 floods from the group buy that wirecat did (Thanks!).

I just got my DC controller from LOR and I can not get these things to fade at all. The red will fade a little bit, maybe from 100% down to 70% and then at 1% they just turn off. The Green don't fade at all. They remain the same brightness from 1% to 100%.

I hooked up a volt meter and sure enough, the voltage is dropping. Staring at 13volts and will go down to 2.5 volts at 1% and then at 0% it goes to zero.

Anybody else having this problem? Are people with D-Light DC boards not have problems with these LED floods?

Thanks.

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You're not the first to ask about the LOR DC boards.

I've had zero problems with Wirekat's MR-16s and D-Light DCx16 boards. I demo'd them at the FL-Mini and the fading was smooth as silk. We even tested them underwater, (OKC and FL Minis), with no ill effects. I don't have any LOR boards so I'm not able to help you with a fix other than to tell you to give Dan at LOR a call for a firmware fix.

This's not meant as a flame or anything aimed at LOR, but since the DC based boards are perfect for 12v DC applications, why didn't they do a few burn ins? Betas?

Maybe TomB might have an answer?

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Thanks for the info Annalisa

I just did some more testing and I don't think they are the Floods. I hooked up a DC power supply to them that allows me to adjust the voltage and the intensity dropped. When I had 6 volts going to them, they were at half brightness.

Looks like I will be ordering a D-Light DC board for my Christmas show this year tomorrow. I can't wait for LOR to fix this problem.

-Richard

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With all due respect, those MR16 lights are dimmable (as d-light seems to show). The problem is that they seem to have (relatively) huge capacitors in them, and this causes the simplest Pulse Width Modulation (PWM) dimming techniques to not work well. I've been playing with some of those same lights using homebrew equipment, and I've been able to dim them by either using PWM with current limiting, or by modulating the current (without any PWM at all).

--

Phil

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Hi Richard --

Yes, I have the same problem. I have sent a MR16 LED flood to Dan and company at LOR. He said they are testing, but I have heard nothing yet.

I'm interested in PSHORT's reply ... I hope Dan sees it ... I think I will PM him to take a look at this thread.

Thanks,

T.

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Dan will probably not find my comments to be very helpful, because the techniques that I use almost certainly would require hardware changes to their board...which would probably interfere with the other uses of that board.

--

Phil

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Playing with my homebrew designs (DC), I observed the same thing as RichardH. What I did notice was that placing a 22 Ohm resistor (s/b 2W or more) in series with the coop MR16 LEDs did seem to increase the dimming range. Not perfect by any means, just an observation, and something to play with.

--

Phil

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I'm playing with a firmware-only technique on my homebrew stuff that looks promising for the WireKat coop MR16 LEDs. Rather than the usual PWM techniques, I just give it a 30 uS (or so) pulse, then delay for a multiple of 30 uS before giving it the next pulse. If the multiple is 0, it's basically full intensity. If I give it a 255 * 30 uS, it's fairly dim (so I need special case code to omit the pulse altogether for 'OFF'). This seems to give a nice ramp over the full range.

Just something to try.

--

Phil

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Phil,

Did you ever have someone tell you something, and by their tone and manner, you know that it is good news ... but for some reason you can't understand a word they are saying. Well, this is true for me.

So, I'm just going to say, "COOL!!!" and pretend I'm not totally stupid, and hope that someone else understands what a 30 uS pulse is and how it might help.

But, keep up the good work ... that's what I love about this place. There are so many "big brains" around, looking at problems from different perspectives, with different skill sets ... that vitually any problem can and will be solved.

Thanks!! Now I will go back to being amazed at my thumbs. And wondering if I have a learning disabililty.:D

T.

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Sorry about the unclear message. It is intended for Dan and any DIYers designing their own controllers, and is hopefully clear to them.

For everybody else, my comments mean that there is a firmware-only way for LOR to provide dimming for the MR16 LEDs from the group buy. Whether they decide to do something, and when, is up to them.

--

Phil

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A Call for Help!

Calling for all those that bought LED floods from the latest group buy of LED floods. See the thread below for details of the group buy. There were two group buys, I bought mine on the 2nd group buy.

http://planetchristmas.mywowbb.com/forum12/14873.html

Please let me know if you were successfully or unsuccessfully in getting these LED Floods to fade. Wirecat was able to get them to fade fine with a d-light DC Board using samples that he received before the buy. Not sure if he has been able to get the latest ones to dim and I am sure he will post some info here.

So if you where in on the group buy, please let me know if you got them working and what your hardware is including your power supply.

Thanks!

Below is a message I sent to others about the issues that I have had the last few weeks.

-Richard

================

I was able to get my hands on a d-light board. Annalisa shipped me one (Thanks Annalisa! Very Nice of You!) so I could try it out.

I hooked up the floods and had the exact same issue as the LOR board with these floods. I tested about 5 different floods (Reds and Greens) from different boxes.

Annalisa tested the board she sent me with her LED floods and it worked find so I know the D-Light board firmware is good for LED floods. She did not test them though with the Floods from the latest Group Buy, just the ones she already had.

I have tested it with two different Power Supplys and also used a 12volt Battery pack (which would be super clean power) and I get the same result. The Leds do not start fading down until they hit 20% and then they just fade a little bit and then go right off.

I have also tried two different USB485 adapters and tried it on two different computers and get the same result.

I also noticed that the Green will dim a little bit more than the red and when you do a "shimmer" the red stays fully lit while the green shimmers just a little bit. It seems like somehow they are holding power. Maybe they have a Capacitor in them or something.

One thing that is strange though is my Battery Pack that I have can switch voltages between 3V and up to 12V. If I hook up a LED flood directly to my battery pack, and change the voltage, it actually changes intensity correctly. 6V from my battery pack will drive the LED at have half intensity but if I use a LOR or D-Light DC board (using 12V as the power source), 6V from the D-Light or LOR Board will drive it at full intensity.

Does not make sense.

==== End of Transmission

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Try putting a 22 Ohm (1W or more) resistor in series with the MR16 LED. With my homebrew design that helped somewhat (although not perfectly). They also seem to work somewhat (again not perfectly) when you try to dim them with a regular AC SSR (with 12VAC).

Both of these are somewhat half-a**ed methods, but they might help.

--

Phil

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I was able figure out that the second group MR16's they sent me were different.

The color printed on the side is larger and the LED array makes a "+" in the middle

while the first buy array has more of a circle.

I tore apart both types and the second buy group has a vastly different circuit board

on it. It has two caps (one 220mf and 100mf), various resisters, diodes and a choke.

The first buy board has one cap (47mf) one res, one small cap and two 2 watt

resisters and what looks like a rectifier.

I should note that even the first buy MR16's don't fade like an incandescent. They

tend to shut off at < 20%.

I ended up with mostly the second buy LEDs so I guess I'll have to use what I got.

To everybody who got the MR16 my sincere apologies. I had no idea the factory

in china would send different product.

Kevin

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Don't sweat it Kevin! In the spirit of PC you were only trying to help the brotherhood/sisterhood and I for one greatly appreciate your efforts. I'm just going to remove the fades in my sequences and wait to see if there is eventually a fix. As a side note, I briefly spoke with Dan at LOR yesterday and although they are very busy they are trying tofix the issue. By the way thecolors look fantastic in my landscape lighting.

Cheers

Daryl

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I got my wife to stop at Radio Shack today (I'm far too busy to go shopping) and she

was able to get two 10 ohm 1 watt resisters (thats all they had). I put them in series

(to get 20 ohms)and in series with a redMR16. Then I put it side by side with the

same red MR16.

The difference is significant. It now shimmers and actually fades better than the

first group buy.

I might get some resisters from Mouser and put them inside my enclosure if I have

time. Just did at .14 ea:

http://www.mouser.com/search/productdetail.aspx?R=MO2CT631R220Jvirtualkey66000000virtualkey660-MO2CT631R220J

THANKS PHIL - You da man!

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Check all of the different colors...they may behave differently, and need different resistor values (between 15-27 Ohms, or so).

Glad to help,

Phil

EDIT: I'm thinking that the power rating of the resistors might want to be increased a bit, perhaps to 5W (especially for the red lamps). The lower wattage resistors might get to be a bit toasty after an extended period of full brightness.

Phil

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Thanks for testing it out wirecat and than you pshort for the idea.

I don know a lot about electronics and have a question. Do I need to put a resistor on every LED Light? I was planning on using 4 channels on my DC board and having 15 floods hooked up to each channel. Can I just put one resistor for the entire channel with all the LEDs on that?

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All of the testing has been done with one resistor per lamp module.

The resistors are cheap. If they are easy for you to get, use one per lamp. If you find them difficult to obtain, experiment with them. Try using one lamp per resistor, then two per resistor, and so forth. The most likely problems are that the lamps lose brightness at the high end, or the brightness varies too much from one lamp to the next.

--

Phil

Edit...I think that 15 lamps per resistor might be too much, I would not try to do more than 4 lamps per resistor. But it won't hurt to try.

--

Phil

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