Quote Originally Posted by MOUNTAIN747 View Post
Christopher, pin 3 is DB5, pin 16 is NC. If you have a 20k pot center taped to Vo you should have contrast. I can vary the contrast on my 4x40 over about a turn and a half of the pot. It goes from almost no visible characters to bright characters. Look over your Vo hardware once more.

Wayne
You have an LCD screen. I have an OLED screen ( I know I put LCD above but it was a mistake). Pin 3 for me is no connection. Putting a POT on pin 3 does nothing. Again, this board does not have a Vo pin.

I suppose you could adjust the contrast by lowering the input voltage if it's really necessary.