I have 2m of WS2812B 144 per metre LED strips. I cut these in to segments of 20 LEDs with the intention of making a 20 x 10 matrix.
On the strip all the LEDs worked. after cutting 6 of the 10 segments have issues. For example;
Blue not working on LED 0
LED 0 not working at all
LEDs 18 and 19 not working
LED 1 green not working, LED 19 not working
LED 18 and 19 not working.
I have been careful when making connections, Not connecting to a live circuit, GND first.
Obviously I have damaged them somehow. Anybody know how? Can you damage them if the solder it too hot (I was using about 340 degrees but reduced it to 240 just in case).
Each comment refers to a different 20 led mini strip which where cut from the initial large strip. The initial large strip (1m of 144 LEDs worked fine).
On 1 strip Blue is not working on LED 0. On another strip LED 0 is not working at all. etc
Ok, I have dealt with this kind of a problem in the past a few times and might be able to help you out.
So, when you say that 6 of the cut strips are not working as expected, I am assuming that you are testing them individually and have not made the matrix yet, correct?
Do you have access to an oscilloscope?
If you look at the datasheet of the ws2812b, you will see that the led has 6 pins, out of which you can see 4 contact pads coming from each LED on the strip. One of those pads is dataout( probe till you can see it on the oscilloscope or simple eliminate all other pads by probing them), and one way to figure out if the strip is damaged is to examine if the data going out of your digital arduino pin is being reshaped by every LED and then being transmitted to the next LED.
I am fairly certain that the problem lies not with the entire strip but with an individually affected LED.