3ds xl bottom screen flashes after repair

I've been trying to repair my 3DS XL as the top screen had a pink hue from shutting down while opening it fully.

Its been almost 9 months since it broke and only tried to repair the screen about 3 months ago and still doesn't work. The first time I had completed it both the screens flashed and it turned off after, I had then replaced the speaker ribbon cable.

After that it refused to turn on with only the bottom screen flashing before it shuts off. I looked at multiple forums threads and decided to buy another screen a few days ago. This screen is from replacebase and have heard good things from that website. However the bottom screen still only flashes after it boots up. I'm not sure if it is a motherboard problem or if I keep breaking the ribbon cable of the Upper LCD somehow.

It charges properly and the blue light turns on, if I open the screen low then it would just stay a black screen. I have not been near any water with the 3ds and it only has a crack on the hinge and a few scratches on the top shell, missing rubber part of the joystick and a few missing screws.

EDIT: I forgot to mention that the loud speakers for the new speaker ribbon cable haven't been soldered on, could that be the problem?