Default [Q] Signal and Antenna layout / schematic

Hello,

Firstly I'm looking for a comment from an expert who has taken Nexus5s apart before. Also I'm beyond the point of returning the phone as this fault developed after replacing a screen and ribbon cable (after I smashed my phone badly). Any help or advice would be great.

So since screen and USB flex replacement on my D821 i notice that my phone signal will connect with full bars, then drop completely, I can also only get 2g where i was able to get higher. The same sim works fine in my nokia. The Wifi Signal is fine and gps works ok but the 'no service' thing makes my phone unusable. I have tried making sure all contacts are clean and even replaced the loudspeaker unit and the black antenna cable but to no avail.

Can someone put up a picture of exactly the components that are involved in the phone signal / 3g setup? Is it possible something could have been damaged on the mainboard to cause this? I can search for networks, connect (sometimes) then it will just cut out.

I tried google for days but cant find a schematic. Basically im trying to determine if there are any other parts i should try exchanging before giving up. It makes no difference how i hold (or dont hold) the phone.

Thanks