Hardware Original 3DS XL’s bottom screen is black- but it’s not the screen that’s the issue (potentially a fuse is blown?)

[IssyUP2U]

3ds works totally fine (touchscreen also works), it’s just that it doesn’t send any image to the bottom screen. I’ve replaced the bottom screen and it made no difference so it’s likely to be a motherboard issue. Is this a blown fuse or something? I was working on my 3DS before this happened so I must’ve messed something up, how do I troubleshoot from here??