Problem with LCD 16x2 on I2C PCF8574T [contrast pot needed adjustment]

[mastakillaman]

I'm trying to show text on 16x2 LCD screen but no luck.
Connection is very simple (all cables connected and checked)

I checked my address and it is 0x27.
Here is a code:

#include <Wire.h> 
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 16,   2); 

void setup() 
{
  lcd.init();
  lcd.backlight();
}

void loop() 
{
  lcd.print("TEST");
  delay(10000);
}

If I remove lcd.backlight(); the LCD blacklight is not turning on. When I put lcd.backlight(); as in the code the blacklight is ON, but I don't see any text there
So because of blacklight is working looks like the LCD receives some signals, but not for text...

What can I try also to make it works?
Many thanks

[mastakillaman]

Tried another library

#include <LCD_I2C.h>

LCD_I2C lcd(0x27, 16, 2);
void setup()
{
    lcd.begin();
    lcd.backlight();
}

void loop()
{
    lcd.print("Hello");
    delay(2000);

    // Flashing the backlight
    for (int i = 0; i < 5; ++i)
    {
        lcd.backlight();
        delay(50);
        lcd.noBacklight();
        delay(50);
    }
    lcd.backlight();
    lcd.clear();
    delay(500);
}

Don't see text but see only blinking of backlight

[mastakillaman]

I need to [quote]
rotate Contrast potentiometer on LCD back
[/quote]