dead pixel stips

razataz327

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Dec 26, 2012
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Didsbury AB
I had ordered 20 ws2812b ..5v 30pixels/m over the last year. I now received a pixel dream colour controller to test them before I put them in my 8ft x 4ft matrix. I bought them all from Ray Wu. Tested them the other day and out of the 20 strips only 10 work. Some of the others flash for a second then nothing. I tested at different points on the strip and no difference. I would hook up a working one to make sure it was not the controller and it appears to be working fine.
I contacted Ray and waiting to resolve this problem.
I am asking the masses why are the strips doing this, can they be fixed if not what can I do with them?
I am not impressed that this many strips are not working.. not good.
As anyone else come across this issue and what did you do?
I am building a matrix to have video and text for my moms 90th birthday bash.
Thanks very much for you help.


Garnet
 

i13

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Not sure if it applies to your particular type of strip or not. I've read from others here that connecting pixels to a controller or tester can break the first pixel if the controller/tester is powered up. This could be the first pixel at any point that you connect it. This would stop the strip lighting up because the broken pixel won't pass the data on.
 

gerry

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Are the connectors (ie pigtails) pre wired or are you adding connecting them yourself ? have you checked that they are correctly wired (I have mine pre wired and use a magnifying glass to check the colours v/s pins) .

And that the direction is also okay ?
 

nzlongfellow

Dennis from NZ
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Hot-swapping strings while powered is like Russian Roulette. Can get away with it sometime but generally, as others have said, you will most likely blow the first Pixel. Cut it out and try the rest, if OK solder in a new one if you need a full string.
 

razataz327

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Didsbury AB
I am using a led2013x mini wireless dream color controller. Made proper connectors, tried the strips with power on or off... check all wiring. I would plug in a working strip, unplug it, then plug in second strip and didnt work. Replugged in the first strip and it works still.
Have tried pixels all through the strip and all it does is flash once then nothing.
On another forum they suggest the timing resolution of the controller may not match the strips. I dont know anything about that.. Any thoughts on that?
Thanks for the help
Garnet
 

i13

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Did you connect the strips to the controller while the controller was turned on? This can break the first pixel in the strip causing the whole strip not to light up. If so then you may have broken each pixel by individually connecting it to each pixel on the strip. Always turn the controller off before you connect/disconnect the pixels.

The timing resolution is probably the clock rate which is a good question. Were all of your strips from the same order? If so then they're hopefully identical so I'd think that all or none of them are likely to have this problem. What does the speed setting on the controller seem to do? This is the only thing I can see that might be the right adjustment.

You could try connecting a bad strip onto the end of a good one (may need power injection). This wouldn't fix the clock rate issue but sometimes pixels don't understand the data from a particular source (in this case that's the controller).

I don't know if it would work if you try connecting the controller in the middle of the strip. You could try this with a good strip to see if it would ever work. I don't know if there are risks in doing this but hopefully someone else will.

Also make sure you're connecting the controller to the correct end of the strip.

Have you heard back from Ray?
 

fasteddy

I have C.L.A.P
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Check to make sure that the cables are connected correctly to the strip, check a good one and then check a faulty one and see if there are any differences. The plug may be connected to the output instead of the input or a wire may be around the wrong way.
 

razataz327

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As stated earlier tried with power on or off.. connections all good.. I would plug one strip in and it worked. Unplugged it tried second strip it did not work. Plugged first strip in again it worked. Tried many different points on second strip did not make a difference. All it does is all the pixels flash once and that is it. So I have about 10 working and 10 not working. Some were ordered at the same time and others came later so different lots.
I asked Ray for a different controller but no reply yet.
I am at a loss
Garnet
 

i13

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We are not trying to ask if you forgot to turn the power on. What we want to know is what order (timewise) you connected things. Did you
1. Connect power to the controller first
2. Connect the strip to the controller second
Or did you
1. Connect the strip to the controller first
2. Connect power to the controller second
The second order is correct and the first order can damage the pixel closest to the controller. Keep this in mind and re-read the thread then it should make more sense.

Does anyone know if it is normal for 2812B pixels to flash white whenever power is first applied? If not then what I’ve explained above is not the issue because it means the first pixel is passing the data on. If the first pixel is passing the data on then it also sounds as though you’re connecting the controller to the correct end of the strip. If the pixels pass the data on then I suspect your strips are working with the exception of the occasional dud pixel if you’ve connected them in the wrong order (above) when testing. I hope Ray hasn’t sent you an incorrect type of pixel but haven’t ever heard of this happening. It is still a gamble to invest in hardware to go with these strips though.

What does the speed setting on the controller seem to do? I hope it is the clock rate but I suspect this can’t be adjusted on your particular controller.
Have you tried connecting a bad strip to the end of a good strip to see if it works then?

These are the only suggestions I now have that you can try without a more configurable controller.
 

razataz327

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Didsbury AB
Hi the link to the strips is http://www.aliexpress.com/item/5m-DC5V-WS2812B-led-pixel-srip-IP68-in-silicon-tube-30pcs-WS2812B-M-with-30pixels-36W/949715127.html


I plug the strip in first then plug in the power. The sets that work come on every time this way. Then I try the sets that dont work. They are plugged in the same way. Using the connectors on the strips so they can only plug in the one way.. data going right way.
The whole strip flashes once when turned on then nothing.
I connected a working strip first then a non working into it. The first strip works and the second one does not work.
Tried non working set then working set plugged into it.. non come on.
I tried different pixels through out the strip and it does the same thing.. flash then nothing.
I appreciate the help.. it is very frustrating and disappointing that only 50% of the strips work and at high price.
Ray is not being very helpful.. he was only willing to send one set and I asked him about the clock rate issue and he had no reply to that.
Here is the link to the controller .. I bought it just to test the strips.. I may have to hook up my Sandevice controllers or my teensy to check them out.
Garnet
 

razataz327

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Dec 26, 2012
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Didsbury AB
This is strange... [font=arial, helvetica, sans-serif]I was trying everything that I could think of. I finally connected all the power leads on the non working strips and they work with all connected to power. [/font]Not sure why they need the extra hook up as the other ones did not. Do you have any ideas why?I have 5 more sets working and the other 5 may have blown pixels ... I will test them later.
Thanks for all you comments and help
Garnet
 

i13

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Well done getting 5 more strips working.

I don't quite understand how you connected the power differently to make 5 more strips work. Did you connect the power to both ends of the strip? If so then it was probably a power issue rather than data. How long is the connection wire between the controller and strip? It won't work if it is too long because power and data can both only travel so far.

I would still try the last 5 non-working strips with a different controller. This is probably the only way around any possible clock issues. The first pixel may have blown with all of the testing so you might need to remove it. I don't know if connecting data at the second pixel will work if the first pixel is still there. Does anyone know?
 
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