To answer your questions:
Q: What is the actual antenna?
Both pcb's are the antenna for wifi and bluetooth respectively as above. The coax cable is not the antenna since its shielded.
Do you mean you found a short between point A and B as shown above? I presume you're using a multimeter. Lets go through the steps.
- You will need to desolder both point A and B from the antenna and then only measure the continuity of the cable. This is because the patch antenna design is a loop and will show as a short. If there is no short, you may solder the coax cable back to the antenna and you're good.
- If there is a short, the problem could be either
- A: there is a short at the motherboard where the coax cable is soldered (between signal and ground). This can be easily identified visually OR
- B: the coax cable has melted and shorted the signal and outer shield during soldering (bad solder job). To identify this you will need to desolder the coax cable from the antenna AND from the motherboard and measure it. This was what happened to me. I replaced the cable with another coax cable I had (initially) and then modded it some more. (will post pic later) OR
- C: the motherboard itself is shorted between the signal and ground, then you're basically screwed!
If you're going to desolder the coax cable, please do it fast or risk melting and shorting the cable. If you're going to desolder the coax cable from the motherboard, please do so only if you're comfortable with surface mount soldering.
Q: Which ground wire do I desolder?
A: Although i advise against desoldering the ground wire, if you must do so its at the ground wire soldered to the motherboard (not in the pic). I will post a pic later...
On a side note, why are you doing this? You had not mentioned it on your post. Are you getting bad signal strength??