I just finished building and I passed the voltage tests. I gave it power via the USB port and the LCD back light is on. But I don’t see any text on the screen. I have no wires connected other than the USB connector. And the backlight is on regardless of the orientation of the switch.
I figured it out myself. One of the pins connecting the lcd board to the main board was loose and was pushed away from the mainboard and didn’t make connection when the lcd board was attached. All I had to do was solder it in place.