Switchbox gives power, But only gives poor Image & Audio

[Andtard]

So when I trying to fix a 5200 I was able to get power via the Switch box. However when the RF cable is plugged into the coaxial no Audio or Image. the TV looks like this:

But when the case opened and the internal RCA jack is used and plugged into the TV no problem, full video and audio. 

So it sounds like I have a faulty Switch box (what a surprise). I then replugged switch box into the coaxial. However after this I applied pressure (finger weight) to internal jack area on the board, and a grainy video was produced via the box. So now I'm unsure as to were the issue is. Is it the switchbox because no video comes out it normally, or is the board. I'm guessing its still the switch box because the internal rca jack works fine, but that doesn't explain why apply pressure to that area increase the boxes performance. If this issue has already been answered please link the page. Thanks for your help. 

       

[Andtard]

Ended up being easy fix. Needed new LM38N chip. works fine now