I was using a Rpi2 and official 7" touch screen display running Ubuntu Mate for about a week without any issues. I've been working on a project with no issues, powered down on Friday, and Saturday, the display would not power on. There was no change in my setup, or in my power supply. Not sure what to do, I went to a local electronics show and purchased a new display and an Rpi3.
When I hooked everything up at home, the second display would not power on, either with the Rpi2 or Rpi3.
I used a brand new SD card and loaded it up with a new Raspbian image, which did not help.
Both boards work with HDMI just fine, but neither will work with the 7" displays. My power supplies are good, I have new equipment, and in both cases, the screen will not power on, will not even show a backlight or give any indication of being hooked up.
I've changed up the power supplies, the power wiring from GPIO, to two individual power supplies, powering through the usb ports between the display driver to the power in micro usb port on the Rpi, and nothing.