820-00165 No wifi hardware detected

[DavutAmana]

Hello,
I don't know what to do on this board anymore ...
The wifi works randomly, I cannot determine why ...

I measured the diode resistance linked to the wifi system but I cannot find any anomaly. What can you advise me to measure?

Thanks in advance

David

 

[2informaticos]

Any history available, liquid sign?
Did you try another airport card?
Clean its connector.

Post U3540 volyages, when the problem appears.

 

[DavutAmana]

Probably a liquid sign, the card comes from an after-sales service of a card already repaired a few weeks ago ...
I do not know more, I have already cleaned it very intensely, yes already tested in several different airports.

Here are the measurements:
PIN 1: 3.3V
2: 0
3: 3.3
4: 0
5: 3.3
6: 0
7: 0.4 - and 1.2v after 30 seconds
8: 0

I just replaced U3440 and U3450. the problem persists.
I think SMC problem, what do you think?

I inform that the card has absolutely no other problem

 

[2informaticos]

"5: 3.3"
5 is ground pin...

"2: 0"
Seems that airport lose power in that moment (3V3_WLAN).
SMC_WIFI_PWR_EN is maintained?

 

[DavutAmana]

Sorry I have inverted the measurements on the 2nd side of the chip.
Here are the good ones:

PIN 1: 3.3V
PIN 2: 0v
PIN 3: 3.3v
PIN 4: 0v
PIN 5: 0v
PIN 6: 0.4v - and 1.2v after 30 seconds (SMC_WIFI_PWR_EN)
PIN 7: 0v
PIN 8: 3,3v

On a functional board I measured only 3.3V on SMC_WIFI_PWR_EN that's why I think an SMC problem ...?

 

[2informaticos]

We need to know if SMC_WIFI_PWR_EN is maintained on the board in repair process.
Do you get 0.9-1V at pin 2/U3540 when wireless hardware is recognized?

 

[DavutAmana]

In fact at the beginning the wifi worked alternately, now it no longer works ...