I can’t get my LCD for my 3d reprap to display. It’s just a blank screen (though on) after I uploaded the firmware (via arduino) to my MKS Gen v1.4 board. The wires appear oriented correctly, the firmware appeared to be uploading. The LCD is 12864, but no characters show.
Have you already turned up the contrast?
@Brook_Drumm I did adjust the knob on the left side of the lcd display. Actually, didn’t know what that was. It looked like a potentiometer knob. But, I don’t think the screen display is the problem.
The screens I use have a tiny pot on the back face of the circuit board as the contrast. If it’s really off from the factory it could look like it isn’t working. But it might be not working for other reasons. Some boards are silk screened wrong, worth trying to swap the cables around or even using the other orientation.
@Jeff_DeMaagd yes, I’ve tried all of that too. There must be something I’m overlooking. Interestingly, the Reprap site stated to remove the comment forward slashes “//“ before the # define LCD display command on the arduino IDE, but it wouldn’t let me do it without generating an error.
On some of the mks Gen boards, the lcd and sd cable plastic things are backwards, you need the red stripe facing the stepper drivers and it should work as expected
@Owen_Smith yes I checked that. Thanks Owen
the only other changes I made to marlin to get it to work are setting the board, including u8glib and setting the display to the right thing. the rest was the same as any other i3 config 
#define MOTHERBOARD BOARD_MKS_13
#include <U8glib.h>
#define REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER
OK, I think I understand. Did you install the u8glib into the Arduino IDE? You either need to find the library on the Internet and put it into the correct directory on your computer or have Arduino IDE put it there for you.
Did the LCD backlight even turn on at all?
Yes, the U8glib library is in there. I’m going to clear my old library out. I keep getting an error telling me one library is invalid.
Owen, I’ve only included boards.h; I had not entered the define MKS 13 mother board. Is that the same as MKS GEN V1.4?
Yes, Jeff the lcd back light turned on