LCD 1602 isn't working

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marmott
 
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LCD 1602 isn't working

Post by marmott »

Hi,

I bought the rgb lcd shield and work on another project with it so I took the lcd screen out of the shield and I have soldered and unsoldered the pins multiple time and I’m not sure he liked it. After my last changes I don’t have white boxes anymore. I’m afraid it’s dead. But it's lighting up, I just have no contrast, I tried a bunch of basic tutorial and it still isn’t showing anything. Here is the basic code I’m uploading :

Code: Select all

/*
  LiquidCrystal Library - Hello World
 
 Demonstrates the use a 16x2 LCD display.  The LiquidCrystal
 library works with all LCD displays that are compatible with the 
 Hitachi HD44780 driver. There are many of them out there, and you
 can usually tell them by the 16-pin interface.
 
 This sketch prints "Hello World!" to the LCD
 and shows the time.
 
  The circuit:
 * LCD RS pin to digital pin 12
 * LCD Enable pin to digital pin 11
 * LCD D4 pin to digital pin 5
 * LCD D5 pin to digital pin 4
 * LCD D6 pin to digital pin 3
 * LCD D7 pin to digital pin 2
 * 10K resistor:
 * ends to +5V and ground
 * wiper to LCD VO pin (pin 3)
 
 Library originally added 18 Apr 2008
 by David A. Mellis
 library modified 5 Jul 2009
 by Limor Fried (http://www.ladyada.net)
 example added 9 Jul 2009
 by Tom Igoe
 modified 25 July 2009
 by David A. Mellis
 
 
 http://www.arduino.cc/en/Tutorial/LiquidCrystal
 */

// include the library code:
#include "Wire.h"
#include "Adafruit_LiquidCrystal.h"

// initialize the library with the numbers of the interface pins
Adafruit_LiquidCrystal lcd(13,12,11,10,9,8);

void setup() {
  // set up the LCD's number of rows and columns: 
  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);
}
}

Thanks for any response.

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adafruit_support_bill
 
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Re: LCD 1602 isn't working

Post by adafruit_support_bill »

But it's lighting up, I just have no contrast,
The backlight circuit is completely separate from the LCD control. So that is not unusual. Most likely all the soldering and desoldering has resulted in some dodgy connections to the LCD controller. If you post some clear photos showing your soldering we can take a look.

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marmott
 
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Re: LCD 1602 isn't working

Post by marmott »

Okay thank you, here is one
IMG_7402.jpg
IMG_7402.jpg (621 KiB) Viewed 183 times

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marmott
 
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Re: LCD 1602 isn't working

Post by marmott »

Here is another one while trying to print something
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IMG_7399.jpg
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adafruit_support_bill
 
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Re: LCD 1602 isn't working

Post by adafruit_support_bill »

I don't see any issues with the soldering. We can't follow the wires to check the connections. An overall view showing the rest of the wiring would help

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marmott
 
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Re: LCD 1602 isn't working

Post by marmott »

Okay great. Here is more pictures
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IMG_7397.jpg
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marmott
 
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Re: LCD 1602 isn't working

Post by marmott »

Another one
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IMG_7395.jpg
IMG_7395.jpg (774.45 KiB) Viewed 169 times

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marmott
 
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Re: LCD 1602 isn't working

Post by marmott »

another one
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IMG_7398.jpg
IMG_7398.jpg (647.32 KiB) Viewed 169 times

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adafruit_support_bill
 
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Re: LCD 1602 isn't working

Post by adafruit_support_bill »

From what we can see, the connections appear to match the code. Sometimes breadboard connections are a little flaky. Check to make sure that all pins are securely grabbed by the spring contacts in the breadboard. If not, try moving them to another hole in the same row for a better grip.

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marmott
 
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Re: LCD 1602 isn't working

Post by marmott »

I dit what you said but nothing changed :(

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Re: LCD 1602 isn't working

Post by adafruit_support_bill »

Can't think of anything else to try. It is possible that the display is just dead now.

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marmott
 
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Re: LCD 1602 isn't working

Post by marmott »

Oh okay, do you know what could be the pin which isn't working? Because I use to see white squares but I don't see them anymore so I assume this is part of the problem.

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Re: LCD 1602 isn't working

Post by adafruit_support_bill »

You need power and ground to the backlight. That part seems fine on your display.
You also need ground and 5v to the LCD controller chip. This is pins 1 & 2.
And you need the contrast circuit. connected to pin 3.

With just those connections, the LCD controller chip should power up. And once the contrast is adjusted, it should show the blocks.

https://learn.adafruit.com/character-lc ... ep-2973891

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