Poor screen resolution and screen flickering after digitizer replaceme

Hi folks,

I replaced the digitizer of an ipad mini (and made sure I disconnected the battery first before disconnecting the LCD). After reconnecting the cables of the new digitizer and the LCD, I tested it and unfortunately the screen is messed up. The apple logo appears and it boots normally but the resolution is very bad and the screen also is flickering. Finally, the backlight is endlessly slowly fading away and returning back. And in the top part of the screen there are white horizontal lines.

Anyone an idea? I handled the LCD very carefully when dis- and reconnecting.

thx Appie