I am also having this problem. My RPi2 is working fine otherwise - I can boot up, use the network etc. My supply is the 1A usb phone charger supplied by CanaKit. The 5V - GND pins measure 4.98 VDC. However, the 3V3-GND pins measures only 0.55 - 0.63 VDC. When I hook up the LED ckt shown above, I can...