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Discussion Starter · #1 ·
so as you might have noticed, I've copied the build of fisure and made it sort of my own.

everything seems to work except for one thing.. some LEDs don't light up..
I've build 2 fixture's both have 24 tri-star LEDs (stevesleds)
-24 ultra violet
-24 red
-12 royal blue
-12 cool blue
each set of red and violet have thier own driver, (24 leds on 1 LDD-700)
the blue are looped and also have 24 LEDs on one LDD-700.
the system runs on a meanwell LRS-350-48 power supply

now here come's the strange thing..
in fixture 1 violet 6-19 doesn't light up and in fixture 2 blue 6-12 doesn't work.
swapping drivers doesn't make an impact.
they all tested OK and function when tested.

I'm a bit confused on what to do now..
I've got a FLUKE 289 at hand but am not that familiar with the settings.
so if there is anything I can messure with the fluke to determine the problem I would really appriciate it.

kind regards
 

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H-violets are listed at 3.7V at 800mA... so guesstimating a V(f) of 3.6 x 24= 86.4 V :eek:..
Your meanwell minus ldd losses is only capable of about 45V per string..

so your lucky any light up at all..or you need to explain your wiring better..
Only way to get all 24 is 12x 2 series/parallel array w/ each series string seeing 700/2= 350mA each

(3.5 x12 = 42V plus 3v for LDD ps needs to be 45v or better)
 

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Discussion Starter · #3 ·
No you're correct they are wired in series.
But the strange thing is that only fixture 1 had this issue and not 2.

Anyhow I'll rewire both fixtures so the violet has 2x12 instead of 1x24 strings.

Thanks for the help ;) bit odd that I figured 24 violets on 1 LDD would work..
 

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Discussion Starter · #5 ·
The 2 fixtures
Fixture 1 is on the right and 2 is on the left, its really hard to see what works and what doesn't but the problem remains the same unfortunetly :(
 

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I've build 2 fixture's both have 24 tri-star LEDs (stevesleds)
-24 ultra violet
-24 red
-12 royal blue
-12 cool blue
each set of red and violet have thier own driver, (24 leds on 1 LDD-700)
the blue are looped and also have 24 LEDs on one LDD-700.
the system runs on a meanwell LRS-350-48 power supply
In post #4, 1st pic, what is the LED that is not lit up?
LED in the center? It does not look like a tri-star?
Looks like a higher voltage COB type LED.

Do you have a sketch of your wiring?

Part count is 72 LED's, but 2 fixtures with 24ea = 48?
How many LDD's do you have?
 

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Discussion Starter · #8 ·
In the middle row are bridgelux, they run on thier own LDD-1000 and are working fine ;)

But 7 violet don't light up in fixture 1 and 3 blue in fixture 2 the rest is working fine.

The colored are powered by 6 LDD-700 drivers
1 for red in fixture 1
1 for violet in fixture 1
1 for red in fixture 2
1 for violet in fixture 1
1 for Royal blue in both fixtures
1 for cool blue in both fixtures
 

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Well it wasn't the LDD but the power supply limits..
Well both really... ;)

LDD is really a current controlled buck voltage regulator..Which in this case will out max voltage but due to it being low will never output its rated current..
Reds are the same but your output is better (go guarantee it hits full of the LDD though) because red's V(f) is like 2.3-ish V.. 55V :eek:

This is for a constant voltage array but it will get you an idea of possible and impossible strings..
http://led.linear1.org/led.wiz

Anyways, if you have one that works and another that doesn't .. same exact config, you need to start looking at little things. Like if any of the solder points are "bridging" to the heat sink.
Using a VOM set to the lowest Ohms channel, you can put pos to neg across a single diode and it should dimly light.
Then pos to pad neg to heat sink.. reverse and repeat neg to pad pos to heat sink ..



Redo any that light if you touch pad and heat sink w/ the correct polarity of course.

just for reference:


Blues have the same issue probably.
Part of it could be lot variations of v(f)
 

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Thanks Jeff will try that, but if that is the case how do I fix it?
Just de-solder and re-solder.. Usually just a small edge "bit" that overhangs the insulating coating on the top of the star..
Bridges the pad to the star "base"..

FYI:
Remember that when you run 2 series strings in parallel they will "split" the amps.. BUT.. if one goes out (say wire breaks) all the "split" current will run to
the remaining string..
so 2 w/ a 700mA LDD will each be at 350mA until one goes "off line', then the full 700mA will be driving the remaining string..
Many people fuse each at, in this case, say .5A so it will blow instead of driving the one at 700mA
 

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Discussion Starter · #15 ·
Thank you very much, it was indeed the case that it was bridged to the heatsink.
I'm going to resolder it tomorrow and retest it

But the leds should be fine at 700ma, didn't think of fuses maybe I'll fit them anyway
 

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Discussion Starter · #17 ·
Thanks again Jeff, all the leds are working now and are now running on 350, I'll order fuses tomorrow and fit them ;)
 

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Discussion Starter · #19 ·
yeah buying them is easy, retro fitting everything would be a complete nightmare :(
I'll just go with the fuses, it doesn't have to be elegant, it has to be functional in my opinion ;)

I'm more than happy that everything is working properly now :)
 

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Discussion Starter · #20 ·
Well I've run into the next problem..
I've 3 power supply's, I tied all the "-" together and to the controller "-".
The power supply first in line is working fine and the leds dim.
But the second doesn't dim.. 3rd is not connected becuase I was trying to troubleshoot..

Basically the Vero don't dim, they are supplied by LDD-1000h.
Each Vero has its own LDD

All the colored leds are working fine


Edit: might be the problem that I'm trying to run 12 LDD's from 1 PWM signal..
I've come to think that the signal is not powerfull enough to be fed to 6 or more LDD's
 
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