PROBLEM: LCD shows squares on half of the screen!

Good Afternoon guys,

I’m an arduino noob and this is probably an easy fix but I really don’t know what to do. I’ve checked the wires multiple times, all are good. Re-soldered V0 as I believe the problem lies there. Other than that I don’t really know what else to do.

Here is my physical setup:

Potentiometer adjusted halfway.

When I adjust the potentiometer fully one way.

Here is the post I have been following:

Airsoft Bomb

Here is the schematic I’m following and the code:

/////////////////////////////
//      Airsoft Bomb       //
// by Malthe Falkenstjerne //
/////////////////////////////

#include <Keypad.h>
#include <LiquidCrystal.h>
#include <Tone.h>
#define pound 14

Tone tone1;

int Scount = 12; // count seconds
int Mcount = 10; // count minutes
int Hcount = 0; // count hours
int DefuseTimer = 0; // set timer to 0

long secMillis = 0; // store last time for second add
long interval = 1000; // interval for seconds

char password[4]; // number of characters in our password
int currentLength = 0; //defines which number we are currently writing
int i = 0; 
char entered[4];

int ledPin = 4; //red led
int ledPin2 = 3; //yellow led
int ledPin3 = 2; //green led

LiquidCrystal lcd(7,8,10,11,12,13); // the pins we use on the LCD

const byte ROWS = 4; //four rows
const byte COLS = 3; //three columns
char keys[ROWS][COLS] = {
  {'1','2','3'},
  {'4','5','6'},
  {'7','8','9'},
  {'*','0','#'}
};
byte rowPins[ROWS] = {5, A5, A4, A2}; //connect to the row pinouts of the keypad
byte colPins[COLS] = {A1, A0, A3}; //connect to the column pinouts of the keypad

Keypad keypad = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS );


void setup(){
  pinMode(ledPin, OUTPUT); // sets the digital pin as output
  pinMode(ledPin2, OUTPUT); // sets the digital pin as output
  pinMode(ledPin3, OUTPUT); // sets the digital pin as output
  tone1.begin(9);
  lcd.begin(16, 2);
  Serial.begin(9600);
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Enter Code: ");
  while (currentLength < 4)
  {
    lcd.setCursor(currentLength + 6, 1);
    lcd.cursor();
    char key = keypad.getKey();
    key == NO_KEY;
    if (key != NO_KEY)
    {
      if ((key != '*')&&(key != '#'))
      { 
      lcd.print(key);
      password[currentLength] = key;
      currentLength++;
      tone1.play(NOTE_C6, 200);
      }
    }
  }

  if (currentLength == 4)
  {
    delay(500);
    lcd.noCursor();
    lcd.clear();
    lcd.home();
    lcd.print("You've Entered: ");
    lcd.setCursor(6,1);
    lcd.print(password[0]);
    lcd.print(password[1]);
    lcd.print(password[2]);
    lcd.print(password[3]);

    tone1.play(NOTE_E6, 200);
    delay(3000);
    lcd.clear();
    currentLength = 0;
  }
}

void loop()
{
  timer();
  char key2 = keypad.getKey(); // get the key
  
  if (key2 == '*')
    {
      lcd.clear();
      lcd.setCursor(0,0);
      lcd.print("Code: ");
      
      while (currentLength < 4)
        {
          
          timer();
          
          char key2 = keypad.getKey(); 
          if (key2 == '#')
            {
              currentLength = 0;
              lcd.clear();
              lcd.setCursor(0,0);
              lcd.print("Code: ");
            }
          else                  
          if (key2 != NO_KEY)    
            {
              
              lcd.setCursor(currentLength + 7, 0);
              lcd.cursor();
              
              lcd.print(key2);
              entered[currentLength] = key2;
              currentLength++;
              tone1.play(NOTE_C6, 200);
              delay(100);
              lcd.noCursor();
              lcd.setCursor(currentLength + 6, 0);
              lcd.print("*");
              lcd.setCursor(currentLength + 7, 0);
              lcd.cursor();
            }
        }

      if (currentLength == 4) 
        {
          if (entered[0] == password[0] && entered[1] == password[1] && entered[2] == password[2] && entered[3] == password[3])
            {
              lcd.noCursor();
              lcd.clear();
              lcd.home();
              lcd.print("Bomb Defused");
              currentLength = 0;
              digitalWrite(ledPin3, HIGH);
              delay(2500);
              lcd.setCursor(0,1);
              lcd.print("Reset the Bomb");
              delay(1000000);
            }
      else
        {
          lcd.noCursor();
          lcd.clear();
          lcd.home();
          lcd.print("Wrong Password!");
    
          if (Hcount > 0)
            {
              Hcount = Hcount - 1;
            }
    
          if (Mcount > 0)
            {
              Mcount = Mcount - 59;
            }
          if (Scount > 0)
            {
              Scount = Scount - 59;
            }
        delay(1500);
        currentLength = 0;
  
        }
      }  
    }
}

void timer()
{
  Serial.print(Scount);
  Serial.println();
  
  if (Hcount <= 0)
  {
    if ( Mcount < 0 )
    {
      lcd.noCursor();
      lcd.clear();
      lcd.home();
      lcd.print("The Bomb Has ");
      lcd.setCursor (0,1);
      lcd.print("Exploded!");
      
      while (Mcount < 0) 
      {
        digitalWrite(ledPin, HIGH); // sets the LED on
        tone1.play(NOTE_A2, 90);
        delay(100); 
        digitalWrite(ledPin, LOW); // sets the LED off
        tone1.play(NOTE_A2, 90);
        delay(100); 
        digitalWrite(ledPin2, HIGH); // sets the LED on
        tone1.play(NOTE_A2, 90);
        delay(100); 
        digitalWrite(ledPin2, LOW); // sets the LED off
        tone1.play(NOTE_A2, 90);
        delay(100); 
        digitalWrite(ledPin3, HIGH); // sets the LED on
        tone1.play(NOTE_A2, 90);
        delay(100); 
        digitalWrite(ledPin3, LOW); // sets the LED off
        tone1.play(NOTE_A2, 90);
        delay(100);
      }
    } 
  }

  lcd.setCursor (0,1); // sets cursor to 2nd line
  lcd.print ("Timer:");

  if (Hcount >= 10)
    {
      lcd.setCursor (7,1);
      lcd.print (Hcount);
    }
  if (Hcount < 10) 
    {
      lcd.setCursor (7,1);
      lcd.write ("0");
      lcd.setCursor (8,1);
      lcd.print (Hcount);
    }

  lcd.print (":");

  if (Mcount >= 10)
    {
      lcd.setCursor (10,1);
      lcd.print (Mcount);
    }
  if (Mcount < 10) 
    {
      lcd.setCursor (10,1);
      lcd.write ("0");
      lcd.setCursor (11,1);
      lcd.print (Mcount);
    }
    
  lcd.print (":");

  if (Scount >= 10) 
    {
      lcd.setCursor (13,1);
      lcd.print (Scount);
    }
  if (Scount < 10) 
    {
      lcd.setCursor (13,1);
      lcd.write ("0");
      lcd.setCursor (14,1);
      lcd.print (Scount);
    }

  if (Hcount <0) 
    {
      Hcount = 0; 
    }

  if (Mcount <0) 
    {
      Hcount --; 
      Mcount = 59; 
    }

  if (Scount <1) // if 60 do this operation
    {
      Mcount --; // add 1 to Mcount
      Scount = 59; // reset Scount
    }

  if (Scount > 0) // do this oper. 59 times
    {
      unsigned long currentMillis = millis();
  
      if(currentMillis - secMillis > interval) 
        {
          tone1.play(NOTE_G5, 200);
          secMillis = currentMillis;
          Scount --; // add 1 to Scount
          digitalWrite(ledPin2, HIGH); // sets the LED on
          delay(10); // waits for a second
          digitalWrite(ledPin2, LOW); // sets the LED off
          delay(10); // waits for a second
          //lcd.clear();
        }
    }
}

Any help would be appreciated!
Cheers, Nick.

P.S, Tell me if you require any other information/photos.

Two things are clear.

One is that the code is actually successfully writing to the display. Generally speaking, the correct adjustment of the contrast potentiometer is at the end towards ground. Obviously, you simply set it so you can see the characters most clearly and leave it at that.

OK, I see no glaring mistakes in your code - you are setting it up as 2 lines of 16 characters. Please correct your first post above to frame the code part with "code" tags, not "quote" tags.

Sad to say, it appears that your display is faulty. This may possibly be corrected by checking the tension of the display to its PCB and adjusting the metal tags that hold it in place. It is possible with extreme care to disassemble and re-seat the "Zebra strip". Otherwise, it's simply toast.

I think "extreme care" also means not touching the strips and or theirs contacts with your fingers. And be sure that you touch those areas with clean tools (if you decide you still have to use your fingers, wash your hands immediately before touching those). Just to make sure you understand that.

Thanks for your feedback guys!

I’ll source another and see how that goes.

Much appreciated,
Nick