I have a matrix that is 14 strings of 2812b 30 pixels per meter 3 meter long strips. I am running it off a P2, 7 strings off each port. The strings on port 1 are powered from the same power supply that powers the P2 The strings on port 2 are from a separate power supply Both power supplies are the 5v/350w from Ray Wu. I've had the first 7 strings (top half of the matrix) working for a few days now and today I finally got the second power supply wired up and connected it to the second set of pixels. The second set didn't work, so I swapped the power connectors (i plugged the first set into the second power supply and the second set of pixels into the first power supply). Now the first set of pixels doesn't work either. I used a spare pixel strip straight into the P2 and it works, so I'm thinking maybe I toasted the first pixel on each set of my matrix. I tested the end of the strips and am getting 5v so I know they are getting power. Does this sound like something that could happen? Was there something else I was supposed to do to use 2 power supplies with one P2?