60 LED/meter 4 meter reel behaving oddly

[finleyben]

I just received and order of 57 meters of neopixels and promptly had my students test them to make sure they arrived in working order.

All but one reel passed with flying colors.

When this strip was first plugged in only 3 pixels lit up, when we checked again all but the 3rd pixel lit although the colors were not correct for the strand test.

Currently the offending strip will not light the 3rd pixel, and the 4th pixel flashes erratically, it also shifted the color of the rest of the strip while running the strand test.

If you flex the strip just a little bit at the 3rd pixel it works properly. My assumption then is that a solder connection on that LED is bad.

Can the strip be replaced ?

Here is a quick video of offending strip.

http://youtu.be/rgM0G9qWyjk

[adafruit_support_mike]

Yeah, that looks like a dead pixel.

NeoPixels have a neat way of passing control signals along the strip: each chip consumes the first 24 bits it sees on its DI pin, then copies the rest to its DO pin. Each pixel acts as a signal buffer for the next one, which eliminates all the problems of managing a long data transmission line. Unfortunately, when you lose one pixel, all the others beyond it lose their signal.

In this case, it looks like the third pixel in that strip has a marginal pin connection. It was probably good enough to pass our QA test on the reel, but became intermittent when you unrolled it.

We can replace that one. Send a note to [email protected] with a link to this thread and the folks there will help you.

[finleyben]

Thank you