LCD 16x2 showing only blocks

Hello people,
I started to learn Arduino and make my projects a several weeks ago and finally I have some hardware arrived and did some test. I bought this display with i2c interface:

I download library LiquidCrystal_I2C GitHub - johnrickman/LiquidCrystal_I2C: LiquidCrystal Arduino library for the DFRobot I2C LCD displays and did upload examples to my Arduino Uno and change the code for correct address, which i check

Now i have just one row blocks on the screen and not the letters. Can you advise me, what I doing wrong.

here are the pictures : https://photos.app.goo.gl/CnbTFpNBTqVPWApT9

Hi, please post your code and pictures here on the forum, as explained in the forum guide.

This picture is not very helpful by itself.

I have bought several 1602 and 2004 displays from Ali Express. Some of them was bad and I opened a dispute on them and got the money back.

The worst case was when ordering 5 2004. Only one worked.

Have you soldered the i2c PCB to the LCD? Just pushing it on will not work.

OK, you have power but no communication with the backpack.

You are using some sort of "LiquidCrystal_I2C" library. Probably the oldest built into the IDE which worked on one particular backpack which is quite likely, no longer available, yours is different; a newer design (but still quite old :sunglasses: ).

In the IDE, using the Library Manager, install the "HD44780" library by Bill Perry. That will install a number of examples which firstly allow you to test your display and find its configuration. The examples can then be used to produce your own code for whatever purpose you fancy. :grinning:

PaulRB:
Have you soldered the i2c PCB to the LCD? Just pushing it on will not work.

Soldering does look ultra-dodgy, in fact despite the backlight working, the last three pins appear not to be connected at all!

Paul__B:

OK, you have power but no communication with the backpack.

You are using some sort of "LiquidCrystal_I2C" library. Probably the oldest built into the IDE which worked on one particular backpack which is quite likely, no longer available, yours is different; a newer design (but still quite old :sunglasses: ).

In the IDE, using the Library Manager, install the "HD44780" library by Bill Perry. That will install a number of examples which firstly allow you to test your display and find its configuration. The examples can then be used to produce your own code for whatever purpose you fancy. :grinning:
Soldering does look ultra-dodgy, in fact despite the backlight working, the last three pins appear not to be connected at all!

You are absolutely correct Paul_B !! thank you so much. The problem was the soldering. I start to practice, just 2-3 weeks ago. But when i did re-soldering of all pins - everything start to work just fine.

Thank you very much guys. This case can be close :slight_smile:

topche:
. . .Thank you very much guys. This case can be close :slight_smile:

You can do this. See item #14 in the forum guidelines.

Don