How to repair screen connectors

Hello.

It's been some months after my Tab S began to give me some problems(screen flickering, battery charging slowly and lasting less...), but 2 days ago the screen started to get a yellowish tint, as if it does not get any blue signal.

Since guarantee has expired, and I don't want to pay someone to repair it(For the price they ask me I have better changing tab), I'd like to try fixing it by myself.

I think the connector bringing the blue signal is detached/broken, but I don't know where it can be!

I even noticed that if I put some pressure in the mid-upper part of the screen(see the image attached), the colors turn back to normality... What can be the problem and how can I try to fix it?

Thanks,

Matteo.