How to detect a Ws2811 bad pixel

[MikelMD]

Hi all, I have a string of 23 WS2811 pixels and after number 13, no pixels light up.  I have confirmed it is not a configuration issue, I used a spare set of lights and all 23 light up.  So, how do I figure out which pixel is the culprit?

[Bwinter]

It could either be pixel 13 (it lights up okay, but failing to send out data to pixel 14) or it could be pixel 14.  On the rare occasions I've encountered, this, I've snipped out both pixels and the rest of the strip has been fine.

[jnealand]

I usually cut after the last pixel and then using my test rig I use alligator clips to connect to the first pixel not lighting up and see if the string works from that point on.  If the cutoff part works then it would be the last pixel lighting up that is not sending data forward.   Also in many cases a real close inspection of the wire between the working and non working part may reveal a bad connection/loose wire.  Found two of those just last week as I was testing some of my older lights before putting them up.  Actually these were lights that I have used the last 5 years so got pretty good used out of them.

[rstehle]

On every Pixel failure I have ever had, the culprit has always been the first pixel that doesn't light.

[algerdes]

I follow the same procedure as Jim.  Break the line before the first one that does not light up.  Connect a "test" string of pixels (with alligator clips) and see if they light correctly. If so, the first one that doesn't light is the culprit.  If not, the last of the lit pixels is not sending, and it goes into the bin.


One thing I found handy was to make a "test" string of at least 4 or 5 pixels. 


Of course, if it is cold enough - or there isn't enough time to do troubleshooting - both the last lit and the first not-lit go to the bin.