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LPD8806 Not all LEDs lighting
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

LPD8806 Not all LEDs lighting

by lunarscreams on Wed Jul 08, 2020 2:26 pm

Hello,
I'm having issues with the LPD8806 LED strip (LPD8806 x 48 LED 3m)

I have digital input attached from the opposite end of the power in, 5v power supply from Adafruit (the suggested one)
Testing with Colorswirl code and the code that changes them with what's displayed on screen with an Arduino Uno. The lights that work do behave as they are supposed to

Initially only the first four from the data end were working. There was a factory joining point that I resoldered, then the first 8 lit up. I squished the chips on both sides as suggested.
Then about half of them lit up, squished those chips, now it's back down to about a quarter of the LEDs lighting up.
I should mention I made the mistake of not testing these before cutting and resoldering into a rectangle for the back of a tv. But also that none of the joints that have issues so far are what I initially soldered at the corners.

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Re: LPD8806 Not all LEDs lighting

by adafruit_support_bill on Wed Jul 08, 2020 2:43 pm

I have digital input attached from the opposite end of the power in

Do you have a ground connection to the processor on the same end as the signal input?

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Re: LPD8806 Not all LEDs lighting

by lunarscreams on Sat Jul 11, 2020 11:23 am

Yes I do

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Re: LPD8806 Not all LEDs lighting

by adafruit_support_bill on Sat Jul 11, 2020 11:31 am

Please post some photos showing the soldering and connections.

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Re: LPD8806 Not all LEDs lighting

by lunarscreams on Sat Jul 11, 2020 12:07 pm

4.jpg
4.jpg (30.06 KiB) Viewed 36 times
2.jpg
2.jpg (35.45 KiB) Viewed 36 times

1.jpg
Admittedly, the worst on. intended to be temporary
1.jpg (36.04 KiB) Viewed 36 times

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Re: LPD8806 Not all LEDs lighting

by adafruit_support_bill on Sat Jul 11, 2020 12:45 pm

Sounds like you may have a few solder-joint failures on the strip itself. These can occur if the strip is coiled too tight or over-flexed during handling.

Were these purchased direct from Adafruit, or one of our distributors?

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Re: LPD8806 Not all LEDs lighting

by lunarscreams on Sat Jul 11, 2020 2:13 pm

DIrect from Adafruit

Order No: 2296509-1838000378

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Re: LPD8806 Not all LEDs lighting

by adafruit_support_bill on Sat Jul 11, 2020 2:55 pm

OK. Please contact support@adafruit.com with a link to this thread for a replacement.

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Re: LPD8806 Not all LEDs lighting

by lunarscreams on Wed Aug 05, 2020 11:33 pm

Hello, Thanks for the replacement, but I am still having mostly the same problems.
I tested the roll as was received and it worked as it was unrolled. but then I guess stretching it out to roll around corners.... Lighting fails and flickers around non - soldered joints. I can squish some chips and they'll pretend to work for a little while, But it is not reliable

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Re: LPD8806 Not all LEDs lighting

by adafruit_support_bill on Thu Aug 06, 2020 5:40 am

The strips do not like sharp bends or repeated bending. Since the backing is flexible but the chips are not, all the stress of bending is concentrated on the solder joints. And since solder is not such a strong metal, the joints do crack and fail.

If pressing on a chip makes it work, you can often repair the solder joints by just re-flowing them with the tip of a hot soldering iron.

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