2004 LCD partially doesn't work

I bought a Arduino UNO R3, connected 2004 LCD to it.

But It works weird. most of parts of LCD works fine but only, third row(entirely) and fourth row’s 14 pixels from left seem to be dead.

As you know, normal LED pixels look dimly purple when they got off(dark, no letter) but these pixels look transparent.

I think the LCD’s controller even can’t connect with these pixels…

I tried to fix the problem, but can’t find any problems.

my Arduino board is new one, the Breadboard and the Sketch is just a example.

As I read previous topic, I opened the bezel and cleaned it, but it doesn’t helped.

What I should do? 2004 LCD is not cheap for me and I even didn’t picked the LCD film(maybe it was fail out?)

  • This post may looks strange because I’m a Korean high school student. sorry for my poor English :cold_sweat:

Welcome on the Arduino forum (your English is good enough)

There are a number of possible causes:

Can you post

  • your sketch used.
  • link to the LCD library.
  • schematic how you connected the LCD (which pins)

can you post a photo showing the dead pixels?
you might need to try a few different camera angles to see it.
have you ever supplied the lcd with a voltage outside of the usual 4.5 to 5.5V range?
have you ever left it getting a seriously incorrect message from an i2c scanner or comparable configuration finder for more than two minutes?

Apart from the dead pixels, can you get it to display your “hello world”?

It is possible, during i2c scanning, to load and set random ugly characters, which persist after the lcd is switched off and switched on. Can you put an lcd.clear() and lcd.home() in setup() of your hello world and say if the fault still persists.

ad2049q:
It is possible, during i2c scanning, to load and set random ugly characters, which persist after the lcd is switched off and switched on. Can you put an lcd.clear() and lcd.home() in setup() of your hello world and say if the fault still persists.

What ?
I don't understand what you are asking in that first line, and am wondering if the OP will understand it.
Doesn't an initialization of a LCD do an erase and a home already ?

It is possible, during i2c scanning, ...

Where did the original poster mention anything about I2C?

Don