I2C interface issue at LCD2004

[asuz]

I have got a few LCD2004 20X4 lcd screen. When I use the I2C interface(red one Funduino brand) there is no problem but when I use black one MH brand there is nothing at the screen. Is there anybody to have idea?

[Shardan]

I've some of these black PCBs running without problems.
Well, I assume that they are same, nothing is really sure with our chinese friends...

Anyays i often noticed that the small blue trimmer is fully turned to one end and nothing is visible.

So first question: Did you already try turning the trimmer? It's the contrast setting for the display.

Second question: What does I²C-Scan say?

[asuz]

I've some of these black PCBs running without problems.
Well, I assume that they are same, nothing is really sure with our chinese friends...

Anyays i often noticed that the small blue trimmer is fully turned to one end and nothing is visible.

So first question: Did you already try turning the trimmer? It's the contrast setting for the display.

Second question: What does I²C-Scan say?

Ohhhh, thank you very much. Turning the trimmer fix the issue

[Shardan]