Does the 3v3 carried in the FFC cable at the display header of the Pi 3 B+ supply power to the 7" touch display? Or do I need to supply power at J1.1 and .5? If so this power can be pulled from the Pi 3 board on the I/O expansion header??
There's two ways to power it.
- With a USB-A to microUSB cable. Plug that into the USB-A socket on your screen, plug the microUSB into your RPi. Connect your wall-wart power supply to the microUSB on the screen.
- With two dupont wires, one on pin#2 or pin#4 (connected the the 5V pin on the display) the other on pin#6 (or any other GND pin connected to the GND pin on the display). DO NOT connect those middle two pins (grey and white wires in this photo).