MacBook Air 2019 820-01521-02 not turning on

We got an MacBook Air 2019 with is not turning on.
Does anyone have a schematic diagram for it, I found one link on forum but is locked can't download?
Thanks for schematic for this Mac.
I have question actually trying to repair this board.
I have checked laptop drain 20v 2A from charger
there is 3.3v 5v G3H present
power button have 3.3v once pressed changing PMU_onoff_L.
no voltage for CPU on L7410,L7430,L7210,L7290
This little LED next to battery connector is not lighting up battery voltage present
any ideas? I didn't fix this boards before not sure if they have any week points ?
Board wasn't liquid damage laptop looks ok no physical damages.
Any help appreciated.


Staff member
You didn't post exact PPBUS_G3H voltage.
Just went for CPU voltages and we don't know anything about other secondary voltages.

This could be another T2 firmware issue, like many of these f***g boards; use search function on the forum...
Okay i have tried T2 firmware. it tried restore in DFU mode and Recovery I getting only error:
AMRestoreErrorDomain 10 - Failed to handle message type StatusMsg) [AMRestoreErrorDomain ? 0xA (10)]
also I do some research on google and looks like when laptop is in DFU mode it should show in USB Devices Tree as two: one Apple T2 Controller and second iBridge. iBridge is missing.
Any more ideas ? I will have to back to secondary voltages I think check it all.


Staff member
Post voltage for other big coils.
Also check all voltages from page 67.

BTW, someone reported to got T2 recovered only at third attempt...
okay I have done some measurements

pp3v3_g3s 3.39v

pp3v3_g3ssw_sns 0v

pp3v3_s5 0v

pp1v8_g3s 1.8v

p3v3sen_ss 0v

pp5v_3gs 5v

pp3v3_g3g 3.29v

Ppbus_g3h 12.64v
tested only on charger, without battery.
I have tried many times restore this t2, chip want take firmware tired restore on OSX Catalina and Mojave no luck two different laptop also errors only nothing more. Have tired in DPU and restore mode.
any help much appreciated
according to apple website warranty expired so they brought it to get it fix if possible.. Its actually 2018 so very first ones I guess
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Looks like this was a EU purchase so you will have at least 2 year warranty if you can provide the original purchase invoice claiming EU consumer law. Do not mess with this T2 stuff unless you are 100% out of any sort of reclaim with Apple.