# Arduino TC1602 no display but backlight

I am using an Arduino Uno and TC1602 LCD display to write from MCU to the module. I have checked the wire connection for a lot of times, but still only backlight no text. So I am wondering whether there is possible that the display function has been burned out? Is there possible that the backlight works well but the display text is damaged?

I have it connected as follows from the Arduino LiquidCrystal page:

And the code taken from the same page is as follows:

// include the library code:
#include <LiquidCrystal.h>

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

void setup() {
// set up the LCD's number of columns and rows:
lcd.begin(16, 2);
// Print a message to the LCD.
lcd.print("hello, world!");
}

void loop() {
// set the cursor to column 0, line 1
// (note: line 1 is the second row, since counting begins with 0):
lcd.setCursor(0, 1);
// print the number of seconds since reset:
lcd.print(millis()/1000);
}

• I hope the software part is correct. Damaged pins is another possibility. Jun 18 '14 at 8:53
• @nidhin I used the sample code inside sketch.
– Zhu
Jun 18 '14 at 9:01
• The backlight is normally just LEDs seperate from the controller so one working without the other is certainly possible. If it's never worked it might be worth posting the code you're using and a schematic diagram of how they're connected. Jun 18 '14 at 9:05
• @PeterJ I follower the schematic on the arduino.cc: arduino.cc/en/uploads/Tutorial/LCD_bb.png; and the code is the "Hello World" in Examples.
– Zhu
Jun 18 '14 at 9:13
• @Gerben I did not use the potentiometer cause I did not have one for now. Then I just left the pin3 of LCD. And there is no difference whether I disconnect the digital pins or not.
– Zhu
Jun 18 '14 at 9:31

## 2 Answers

You need to set the contrast. The contrast is probably too low, making the "hello, world!" virtually invisible.

You can try out some combinations of 2 resistors, to create a voltage divider yourself. My 2 LCD displays need V0 to be 0.8V and 1.1V respectively, to give you some indication.

Based on your diagram, you have no power going to the backlight.

Most LCD modules needs two sources of power (commonly 5v and 5v) one for the module itself and one for the backlight. With The smaller modules, that comes in most starter kits, the 3.3v on the Arduino is enough to power the backlight.

The last two pins on the LCD marked "BLA" and "BLK" are the negative and positive for the backlight. Depending on you LCD module you can use the 3.3v and 2nd GND on your Arduino to power the backlight.