MacBook Air 1466 820-00165-A keyboard ON/OFF not working

[mferna14]

Hi all, I am working on a MacBook Air A1466 820-00165-A logic board. There was a liquid spill on U5480 and all corroded. It was not turning on. After I replaced U5480., the logic board has come to life & I get perfect display & boots to OS well. Only one problem, the logic board turn on fine after installing the battery & powers down well with the keyboard power on/off button by pressing it more than 3~5 sec. But when I want to turn on the unit from the keyboard's on/off button it does not turn on, no matter what I do, unless I remove the battery & put it in again with the magsafe 2 connector plugged in. I checked the Keyboard connector (J4800) voltages, all seems to be fine, except SMC_LID pin # 1 voltage should be 3.42, out here its nearly 2 volts. I checked the circuit & replaced the resistor R5171 (100K) but still the same, does not turn on from the Keyboard ON/OFF button. Replaced the keyboard, Trackpad, All flex cable & the Magsafe2/Audio/USB board, no luck , still same. Any help would be greatly appreciated.

[piernov]

Re: MacBook Air 1466 820-00165-A keyboard ON/OFF not working

SMC_LID at 2V is an issue. Disconnect the keyboard and the flex cable between main logic board and I/O board. Connect only power cable between I/O board and main logic board, and connect Magsafe.
Then measure SMC_LID again. If it is still low, check voltage on both sides of R5171 to make sure one side (at least) is 3.42V, inspect keyboard connector and J9500 for damage, remove C4835.
Also inspect for liquid damage near SMC. If there is liquid damage near SMC, try to reflow it.

[mferna14]

Re: MacBook Air 1466 820-00165-A keyboard ON/OFF not working

Thanks for all the help., it was the SMC I predicted after all the troubleshooting of yours & mine. Now the unit keyboard on/off works fine after SMC re-balling & installation. So I came to know one more problem, if "WiFi hardware not installed" is showing., I was not getting 3.42 volts on the WiFi pin-20 of the slot. I replaced SMC & now the WiFi works fine too on the other board. So thanks for all your help. & once more things in this research, you can use 820-3437-A SMC into 820-00165-A, I just had to reset the PRAM.