About signal strength loss when trying to fix a wifi adapter of a notebook

[mozcelikors]

Hello guys,
A sequence of unfortunate events happened to me today when I was working on my laptop. I use ASUS UX32VD ULTRABOOK and its screen holder apparatus broke. So I opened the back cover to fix it. Unfortunately I stressed the cables that are going to the wifi adapter. (With the golden colored tips). So I soldered the cables on top of the tips (using your regular hot solder), but suddenly signal strength seen by my ultrabook is extremely low, I can connect to internet but barely. How can I fix this? What went wrong? I feel like this can be a good learning opportunity. Thanks for the guidance in advance.

[RGB255_0_0]

Did you short the coax?

[mozcelikors]

I dont think I did. I simply soldered two cable on top of the golden tip. But before they were inside.

[rg58]

What do you mean by 'golden tip'? I think what you mean are 2 golden coax connectors sitting on a small WiFi board. You may have soldered the shield of the cable to the inner pin of the connector accidentially. But I wonder how you managed to solder that anyway. It would help if you could attach a picture. Otherwise, try to test for a short on the connector using an Ohmmeter.

[mozcelikors]

Oh yes you are right. Here is the picture. I hope this helps.

[RGB255_0_0]

Looks to me like you broke the coax and simply soldering the ground when it is the signal cable inside broken.

Now you may need a new WiFi adapter too if that is solder I see...

[mozcelikors]

I see. I didnt realize that. So unless I could solder the cable to inside the connector which seems very unlikely, I should at least get a similar coax cable. I didnt solder anything on wifi adapter end.

[rg58]

Yeah, tough one now. You may want to unsolder them again and clean them up as best as you can. Then try to check for shorts on both, the plugs on the cables and the connectors on the WiFi board (as probably some solder went underneath as well). Then you could check both coax cables for continuity of the *inner* cable which carries the signal, but you need to find the other ends first which are often going all the way into the display panel - can be difficult. In the worst case as the last resort you could try to remove the connectors from the board and solder 2 small, isolated cables (ideal length would be either 9cm, 15cm or 21cm - equal to 3/4, 5/4 and 7/4 lambda) to the signal pins under the connectors, or you could scratch off the coating from the 2 tracks leading away from both connectors and solder your 2 wires there. As I said, this would be the most ugly solution as a last resort.

It should also be possible to operate the WiFi with only the MAIN antenna connected, so if this connector on the board still works you can try to only connect the plug with the white cable to the left input (1 MAIN) - if this cable is OK. Your connection wouldn't be as stable as before though (no antenna-diversity) as it would be more dependent on your laptop's physical position in the room, but the signal should be back to normal in a 'good spot' in the room. RF is tricky and we have to consider reflexions in the room/building etc. with different signal propagation delays, interfering with each other. But basically it should work with only the main antenna connected.

Hope this gives you some clues.