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I've been having intermittent problems with the Internet connection of my HP Envy, which has an Atheros Wifi card. Some googling indicates that this is a fairly common problem with these laptops.

I contacted HP, and after an attempt at a software fix, they asked me to try to reseat the card before sending it in for replacement. They referred me to this document, which describes how to take it apart:

http://h10032.www1.hp.com/ctg/Manual/c04409752.pdf

The diagram

When I got as far as the Wifi card itself, I observed the following diagram in the document (page 60 of the document):

Wifi card removal diagram


Inside the machine

However, what I actually see inside the machine is this:

Wifi card photo

Unfortunately, I already disconnected the wires before taking a picture.

As you can see, the numbers and colors in the diagram don't match reality. What's more, the numbers and colors of the wires don't match the numbers and colors of the terminals. (The number on the black wire is 1, and the number on the white wire is 2, but the card shows white 1, black 2.)


I'm wondering a couple of things:

  1. Do I just trust the numbers of the wires and hook them to the matching numbered terminals on the card? I think that's how they were connected originally, although since I didn't photograph them while connected I'm not 100% certain about this.

  2. What would be the consequence of hooking them up wrong? (I'm wondering if that could possibly account for the connectivity problems I was having before?)

P.S.: I can definitely call HP support about this, but I was very curious to get an opinion from knowledgeable people on this site who I know aren't reading from a script.

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The cables are antennas. Both antennas work the same way so connecting them the wrong way around is fine.

If there is some software that can show you from which direction the signal is strongest, that software would end up getting left and right wrong, but that's all there is.*

There is a small chance that the 2 antennas are specced differently (different impedance). Connecting them wrong would not break anything in that case, but signal reception would be below optimal. Again the chance that the antennas have different specs is small. Connecting them the other way around to test is fine.

Also, sadly, it's very common that manuals with pictures (or even without) don't match reality.

*You may have heard that multi antenna systems can boost the signal in the direction of the router. That isn't a problem here. Switching left and right is not a problem even in this case because if the router is on the left, the system will think the router is on the right (switched), and then attempt to boost the signal to the right which ends up boosting the signal correctly to the left (switched again). Just like -1 * -1 = +1.

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  • Actually, configuring mobile device's antennae for anything other than diversity is bad idea coz advantage of multiple antennae is (more or less) omni-directional. – Free Consulting Nov 2 '14 at 8:03
  • @Free, so: Peter is right saying the antennas are most likely the same, and connecting any way is fine? – Arjan Nov 2 '14 at 11:07
  • @FreeConsulting: With all due respect, I have to disagree. Using multiple antennae for multiple streams and/or beam-forming can be much more effective than restricting it to diversity. It can (at least theoretically) fall back to diversity automatically, but almost never will because it's almost never the best choice. – Jerry Coffin Nov 2 '14 at 11:44
  • @Arjan, yes, in diversity mode station should sample both antennae and regardless is "left" antenna is really on the left or on the right (same for "right" one). – Free Consulting Nov 2 '14 at 13:59
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I see your dilemma. I'd trust the colors and board print over the tags on the wires since they were added by an assembly worker who can easily make a mistake attaching those glued on labels by being in a real hurry to get them on, although the worker and the PDF seem to be in agreement. The screened, firmly mounted label on the card is usually more reliable but it could be what is wrong.

I agree with Peter's answer.

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