Black screen touch works on M31s(very similar to A51 uses same screen)

The original screen showed first logo but nothing after that. I replaced the screen with copy oled for A51. Now it shows logos and android but very dim and colours don't look right. Only always on display works fine. I've got now a original screen but its all black screen. Only always on display mode works there the display works fine and I can see the clock and charging as status. Is this motherboard issue or maybe main flex cable?