Ds lite white screens, what could be the fault?

Hi! So, I have a DS Lite that only has white screens when I turn it on, and changing the screens didn’t change anything so there is a fault on the motherboard somewhere. What could be the fault of it doing that? Both screens work on another motherboard. When I close and open the DS Lite some lines are on the screen, not when I first turn it on by the way. Thanks in advance for any answers!