MacBook Air A1466 820-00165-A No wifi

[Joztu]

Hello,

Please I need help with a macbook i'm working on which has NO WIFI, opened and inspected the board, no visible signs of liquid spill or any damages

I checked the WLAN connector (J3501) in ohms mode and saw pin 1 of the connector was shorted to ground, did voltage injection and U3550 was getting hot, removed it (U3550), tested pin 1 of WLAN connector (J3501) and short was gone, replaced U3550 but now pin 1 of J3550 which is only producing 1.7V which i assume is supposed to b e3.3V


some other voltages i got are:

R3554 pin 2 : 0.4v


LAptop boardnumber : MacBook Air A1466 820-00165-A

[reformatt]

Re: MacBook Air A1466 820-00165-A No wifi

U3550 is a switch. Apple have lots of these around the board to conserve power, and yes, it needs to be 3.3V. Either check your part or check your soldering. I usually apply solder to both the pads and the IC itself and float it into place if I'm using one from a donor.

[Joztu]

Re: MacBook Air A1466 820-00165-A No wifi

U3550 is a switch. Apple have lots of these around the board to conserve power, and yes, it needs to be 3.3V. Either check your part or check your soldering. I usually apply solder to both the pads and the IC itself and float it into place if I'm using one from a donor.

Thanks for your response, as for the IC itself, when I replaced it at first, I got the 1.7v so I thought my reballing was the fault, so I reballed it again and ensure it was well fitted and same result of 1.7v

I'll try replacing it with another u3550 entirely and see if it works, however, if I get the same 1.7v after replacing with a new u3550, would it be ok to run a jumper from pp3v3_5 (pin 2 of u3550 which has 3.3v currently) to pp3v3_wlan_r (pin 1 and 3 of u3550) which is supposed to have 3.3v?

I'm asking since you have better experience than I do, your reply would be appreciated, thanks 🙏

[reformatt]

Re: MacBook Air A1466 820-00165-A No wifi

I've had the same fault previously and replacing U3550 has fixed it. Check resistance to ground for PP3V3_WLAN first. If it's low, then only C3521, the SMC or the Airport card would pull it down. If the resistance is ok, then try another TPS22924C, there are plenty elsewhere on the board if you have a donor.

You could bypass the switch for testing, but its used to switch off the Airport card during sleep to save power.

[Joztu]

Re: MacBook Air A1466 820-00165-A No wifi

I've had the same fault previously and replacing U3550 has fixed it. Check resistance to ground for PP3V3_WLAN first. If it's low, then only C3521, the SMC or the Airport card would pull it down. If the resistance is ok, then try another TPS22924C, there are plenty elsewhere on the board if you have a donor.

You could bypass the switch for testing, but its used to switch off the Airport card during sleep to save power.

Thank you so much, i'll make necessary changes and hope it works, thanks again

[Joztu]

Re: MacBook Air A1466 820-00165-A No wifi

Solved, laptop now has WiFi available


I made a jumper from pin 2 to pin 1 of U3550, tested and WiFi was restored

Thanks so much