I did but it looks like the TH pins work at "+" to make the display digits work. I change the pot resistance that is connected to "-" but it doesn't do anything, the display is blank, because it's connected the right way to work, at "+"
Here's the circuit diagram.
lcd display connect to ground to the right TH pin, but doesn't show characters just blank display.
lcd display connect to "+" the right way to work, to the right TH .