Help with a i2c display and converter

Hello ! I got a i2c display(with the converter soldered the display) and a converter. I tried both with this library https://www.optimusdigital.ro/ro/index.php?controller=attachment&id_attachment=1115 and they didnt work.
The i2c display had all of the top pixels on and the converter attached to a normal display showed nothing.
On the back of the i2c display is: LCM1602 IIC V1
On the back of the converter is: MHKK
Wiring: sda -> a4
scl -> a5
I checked the contrast and it only made the pixels dimmer

Look for bperrybap's "HD44780" in the Library Manager. It also contains the instructions.

Still doesn't work

Edward2005:
Still doesn't work

What did the diagnostic sketch report?

I can not find the diagnostic sketch. Can you tell me the path ?

I can not find the diagnostic sketch. Can you tell me the path ?

In the IDE, File, Examples, hd44780, ioClass, hd44780_I2Cexp, I2CexpDiag.

Edward2005:
I can not find the diagnostic sketch. Can you tell me the path ?

It is in the hd44780 library documentation.
Did you read the included documentation? (It is in a sketch called "Documentation")

It also has links to other information including the hd44780 wiki.

--- bill