One Strip of RGB LED LPD8806 seems Defective

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jjk697
 
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One Strip of RGB LED LPD8806 seems Defective

Post by jjk697 »

I recently ordered 18m of Digital RGB LED Weatherproof Strip - LPD8806 32 LED (10m a few weeks ago and then 8m a few days ago as part of the order number listed below). It appears one 5m strip from the new order is inoperable.

I have followed the advice in the forums: my 5 volt power supply works (a 350 watt computer PSU) for the other three strips and I'm putting data and clock into the proper channels and into the input rather than output. All other strips work on my setup when I swap them out -- both other 5m strips and the 3m strip. I've verified this several times with the "good" and "bad" strip(s).

I unrolled the strip after testing to check for anomalies, but I can't locate anything that stands out to me. Otherwise, the strip wasn't unrolled for the initial testing (same I way I quickly check all my strips). A few (3-4) lights turn on randomly on the strip when powered but that's all I've gotten from it.

I use it on a raspberry pi setup and do have the grounds to the pi and lights properly connected. I power the pi from the 5 Vsb and the strip from another 5v pinout (which I've verified outputs 5.05v) and the strip and pi share a common ground to the PSU.

Again, the same setup works with my other two 5m strips and my 3m strip (the same exact RGB led strip type).

Is it possible to return this strip and if you find it defective, to get a replacement? Or is there some other way I should debug this?

Thanks much!

ORDER:
February 24, 2015
Order #717840-5519359107

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Funman1
 
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Re: One Strip of RGB LED LPD8806 seems Defective

Post by Funman1 »

You may want to try cutting the first LED off, sometimes the first LED goes bad and then never passes on the data to the rest.
Also you did make sure that the data in on strip is correct? I know I've hooked them up backwards before and done a face palm.. LOL

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jjk697
 
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Re: One Strip of RGB LED LPD8806 seems Defective

Post by jjk697 »

Thanks for the reply. I'll try to bypass the first led... and perhaps just work my way up the strip in case it is a flaw further up. I definitely have the data in correct, I've checked it several times and my setup allows me to just swap out led strips for testing by replugging the new strip's JST. All my other strips perform perfectly.

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jjk697
 
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Re: One Strip of RGB LED LPD8806 seems Defective

Post by jjk697 »

I went about a third of the way down the strip and fed in the 5v, ground, data in and clock in. Still nothing. I undid that, then plugged the four inputs into the JST at the beginning of the strip and measured the voltage across all those points 1/3 of the way down the strip. They ALL give +5 volts which, of course, is not what I see directly from the data in and clock in at the JSTs leading into the strip. Does that imply what the trouble is? Somehow everything is shorting to 5v?

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jjk697
 
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Re: One Strip of RGB LED LPD8806 seems Defective

Post by jjk697 »

Can I exchange the defective strip for a new one? I'm stalled on a tray ceiling led install until I can get another 5m of working lights.

Thanks!

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adafruit_support_mike
 
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Re: One Strip of RGB LED LPD8806 seems Defective

Post by adafruit_support_mike »

The 5v readings on the data and clock lines would be normal for a strip with a dead chip somewhere along the way, and it would be extremely difficult to kill every chip in a 5m strip.

Could you post a photo of your connections to the point partway down the strip please? Also, do you have anything like an oscilloscope or logic probe that you can use to measure the signals on the strip itself?

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jjk697
 
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Re: One Strip of RGB LED LPD8806 seems Defective

Post by jjk697 »

I don't have scope, unfortunately. As for the connections, I fed in the 5v and ground from both ends of the strip and simply held the data and clock in position by hand. Should I go along the strip, testing at each in/out cut point in this way? Or can I probe each chip directly with the 5v fed in to see which chip is defective?

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jjk697
 
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Re: One Strip of RGB LED LPD8806 seems Defective

Post by jjk697 »

I emailed support about getting a replacement and they directed me to post here. Is there a different thread I should go to to get help getting a replacement?

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Franklin97355
 
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Re: One Strip of RGB LED LPD8806 seems Defective

Post by Franklin97355 »

Could you post a photo of your connections to the point partway down the strip please?

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jjk697
 
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Re: One Strip of RGB LED LPD8806 seems Defective

Post by jjk697 »

Sure, here is a close up and a further away shot. GND and +5v are brought in at end of strip (and probe correctly at this point in the strip).
gray wire from pin 19 becomes green wire, blue wire from pin 23 stays blue
gray wire from pin 19 becomes green wire, blue wire from pin 23 stays blue
20150306_112610_resized.jpg (223.51 KiB) Viewed 370 times
close up of wires about a third down the strip
close up of wires about a third down the strip
20150306_112447_resized.jpg (275.93 KiB) Viewed 370 times
Oh, and the pi is sending data to the strip in this photo, but no lights are on. This same setup works with my other three strips.

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adafruit_support_mike
 
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Re: One Strip of RGB LED LPD8806 seems Defective

Post by adafruit_support_mike »

I don't see anything out of the ordinary there.

Send a note to [email protected] with a link to this thread. The folks there will get you a replacement strip and arrange return shipping for the strip you have now.

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