LCD Display shows always squares [bad soldering]

Other Hardware Displays
1

Hello,
I have soldered the I2C with a typical 16x2 LCD display and I have this problem that it always shows squares.
I am not sure why it happens, but here is the code

#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// Set the LCD address to 0x27 for a 16 chars and 2 line display
LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
  // Initialize the LCD
  lcd.init();
  
  // Turn on the backlight
  lcd.backlight();

  // Clear the display
  lcd.clear();
  
  // Set the cursor to column 0, line 0
  lcd.setCursor(0, 0); 

  // Print a message to the LCD
  lcd.print("Hello, World!");
  
  // Set the cursor to column 0, line 1
  lcd.setCursor(0, 1);
  
  // Print a second message
  lcd.print("I2C Tutorial");
}

void loop() {
  // Main loop does nothing
}

Any suggestions?

DSC03942
DSC039421920×1280 60.4 KB

2

The squares indicate that the display is correctly powered, but I2C communications are not working.

To check communications, run the Arduino I2C address scanner program.

3

Just ran it and it says
I2C device found at address 0x27

4

Odd. Perhaps the display is nonfunctional. Please post a link to the product page.

I don't know what this means. What is "the I2C"?

I have soldered the I2C with a typical 16x2 LCD display

If you are talking about some sort of I2C LCD backpack, post a link to it, and check whether your soldering job is faulty.

5

Adjust the pot on the back, it may be working but washed out.

6

I do not have the exact page because it is quite old and their website is down, but I found identical product in this page

For the soldering I might post a photo, because this might be 2nd time I ever solder

The pot on the back, I have moved it several times, just changes the brightness, nothing else.

7

Your picture is not clear enough.
Please show a clear picture so we can evaluate your solderings.

8

17269309628868594124370296640224
172693096288685941243702966402241920×2560 156 KB

9

Take a look at the product page you have postet - they show a decent and consistent soldering.
The solder points should shine, solder should be on both side of the mounting hole.

E and D0 seem to be shorted on your picture.
Redo your soldering.

10

Soldering is bad on several pins. Use hot iron (650-700) and liquid flux.

11

Thanks guys, I resoldered it and it worked.

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12

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