Question Replaced broke laptop screen. Backlight working but no picture

Apr 22, 2021
I have a Lenovo Legion Y740-15ICHg that I had in my backpack. Somehow the screen cracked in the bottom right corner so I ordered a replacement screen thinking it'd be easy to replace.
I found the screen model on the back LP156WFG(SP)(B2) and ordered one on amazon that said had the same model number. The first screen I got, the backlight came on but nothing else. I can/could control the brightness with my media buttons but no picture.
Swapped that out for another one. The new screen showed the Lenovo picture for a second but flickered and went away. The backlight is still working and I can control the backlight level with my media keys as well.
I have my laptop hooked up to my tv. I went to device manager and I have two displays in device manager, both say Generic PnP Monitor but still no picture on laptop screen.
Any suggestions on what I did wrong or something I can try?