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Archive for December 3rd, 2015

Neopixel Knockoff: Early Failure

About a week after First Light, one of the knockoff Neopixels (not a Genuine Adafruit Product) suffered an intermittent failure: it worked fine after being off for an hour or two, but eventually stalled at a fixed color, with all downstream pixels equally dead. Of course, it was the middle package in the string of three, buried in the hub (this is before the failure):

Hard Drive Mood Light - low angle

Hard Drive Mood Light – low angle

Spraying circuit cooler on the package brought it back to life for a few minutes, confirming the diagnosis. Reducing the maximum intensity to PWM 32 reduced the average power dissipation enough to let it run for as long as I was willing to let it, although it might not survive a hot summer day.

Not having glued the spacers onto the hub simplified extracting the strip, although warranty repair is always a nuisance. I daubed red Sharpie on the failing LED to avoid losing track of it, then resoldered the LED and capacitor connections to no avail:

Knockoff Neopixel Failure - overview

Knockoff Neopixel Failure – overview

There’s nothing obviously wrong inside:

Knockoff Neopixel Failure - detail

Knockoff Neopixel Failure – detail

The fine details of the WS2812B controller produce a horrible Moiré blur with the camera’s low-res image, but you get the general idea.

Most likely, one of those flying wires isn’t quite bonded, but we’ll never know…

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