Prestigio multipad 4 PMT7077 3G no picture

Hello, i have this tablet and it have broken touchscreen and micro USB connector.

After i replace it the LCD does not show any picture (only backlight turn on)

I order new LCD but it is the same, only backlight turning on and no picture.

I can hear when tablet turn on and when i slide it i hear sound of screen unlocking.

I check the flex ribbon cable and it look ok.

Any idea what to check?

Here is a video