New LCD 1602 I2C shows characters only on HALF of the screen

Hello, pretty new to arduino projects.

Ordered from ebay 2x LCD 1602 with I2C already soldered on them.

One is blue and one is green.

With the same code the green one works just fine, but the blue one works on just half of the screen. The adress on both is 0x27. Tried messing with the pottensiometer but the blocks dont vanish on the half part of the screen that is not working.

The solder points seem fine but i dont have a magnifying glass.

Here is a picture

That photo indicates a defective display.


I see...

I decided to not give up and try one last thing.

I heated all solder pins in case there is some cold joint invicible to the eye but no luck.

I will try seperating the i2c from the lcd and see which part is the defect.

Thank you.

I will try separating the i2c from the lcd and see which part is the defect.

It is of course, the display.

Note (when you have separated them), two black "blobs" on the back of the display PCB. One controls the right side (the "slave"), the other the left (the "master"). There is a broken connection between the two. Not repairable!