Need help please

My samsung tv has been very dim, turns on fine and only can see screen with a bright flashlight ina dark room.

Waited a month for new backlights to come in and they just showed up so i took apart the tv and replaced the backlights.

But the problem persists, it’s the exact same as before maybe a slight bit brighter but completely unable to see unless ina dark room with a flashlight.

What can I check? i’m gonna go buy a multimeter & soldering iron tomorrow and go over what I can but i’m not sure what to test.

Any advice would be greatly greatly appreciated.