GB Pocket boots but no Nintendo logo appears

I've been working on repairing this Gameboy Pocket I got and have slowly brought it back to life. When I got it, it wouldn't boot at all. Now, it always turns on without any issues. Now, however, I've found that it won't read games and when booting without a cartridge, the Nintendo logo doesn't appear, not even the black back that should be there. I've tried three different screens and have found the same thing. The contrast wheel works as well so I'm not sure what's going on.