Why is there a 300 ohm resistor is series with the data input on some strips?

[Greg.Ca]

Check the attached photo first.  This 300 ohm resistor has been causing nothing but havoc. This resistor came from Ray's factory in China with this mysterious heat shrinked 'bump' attached and soldered in series with the data in 'green' wire. As it turns out, this mysterious 300 ohm resistor causes the strip not to light up directly from my P12S . When this resistor is removed (bypassed) from the data in connector, the strip functions correctly.

I have no idea as to why Ray's Chinese workers would solder in a 300 ohm resistor directly in line with the data input connector on my strip. What function does it supposed to perform?

These strips are 5V WS 2812b's with 150 pixels per strip. Any clue as to why that resistor is soldered in place will perhaps help me determine as to why some of my strips are intermittently not working.  The common demonenator as to intermittant defective strips seems to be this pesky 300 ohm resistor that is in series with the data in of the strip. ARGHHHHH!!!!!!!

I ordered 60 these strips from Ray and have a 20% failure rate that seems to be directly related to this resistor. At least 50 of these 60 strips are working somewhat but I need to know what this resistor's function is.

Thanks --Greg--

Any comments??








http://www.digikey.com/en/resources/conversion-calculators/conversion-calculator-resistor-color-code-5-band

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[Steve Gase]

i have some of ray's 5v ws2812b strips (60 pix/meter) but i don't have such a resistor.

as a side note:  just today I was doing a final check on a coro box with one of these strips and grabbed the wrong power cable -- sending 12v instead of 5v.  big mistake, a couple pixels seemed to work afterwards, but many more failed throughout the length of the strip.   oh well...