TomGeorge said:
If so you need at least 7V on Vraw as it is the input to the 5V linear regulator.
cashilysh said:
Yes USB 5V to RAW, I didnt think about it beeing the cause, because the microcontroller was powered and could be programmed.
You have your answer.
It would be better if you ran a separate line from your 5V source to the LEDs rather than pulling it through the Arduino's PCB traces.