I purchased a 5m roll of 2812B LEDs and for the life of me I cannot power them on ? Never played with LED strips before. I have connected a 1m length to my bench power supply white to ground, red to 5V and when I turn the power on I get no lights but about 30ma current draw. Bench power supply goes into CV mode. I even followed the Core arduino tutorial with the same result. I am a beginner but right now I feel completely useless. If I attach the data line to ground it makes no difference. Any suggestions welcome. They cannot be faulty, surely I am missing something.