Macbook Air 2019 A1932 / 820-01521-A No power

[Bogbog]

Hello,

I recently acquired a faulty Macbook Air 2019 A1932 with mainboard 820-01521-A.

Seller claimed that device just stopped working suddenly.

Device does not boot or give any signal of life other than the white led on mainboard.
Using cheap multimeter and microscope I went trough list of semi-random diagnostic steps:

Voltage measurements

Charger in USBC-B (closer to display) everything disconnected.

PP20V_USBC_XB_VBUS 20.7v
PP3V3_UPC_XB_LDO 3.25v
PP1V8_UPC_XB_LDOA 1.81V
PP1V8_UPC_XB_LDOD 1.80V
PP1V1_UPC_XB_LDO_BMC 1.8V
PP1V8_SLP_S2R 1.81v
PP3V3_G3H_RTC 3.3V
PHV_INT_XA_G3H 0V
PP5V_G3S 0V

Charger in USBC-A (closer to trackpad) everything disconnected.

PP20V_USBC_XA_VBUS 5.16v
PP3V3_UPC_XA_LDO 3.32v
PP1V8_UPC_XA_LDOA 1.80V
PP1V8_UPC_XA_LDOD 1.79V
PP1V1_UPC_XA_LDO_BMC 1.11V
PP1V8_SLP_S2R 1.81v
PP3V3_G3H_RTC 3.3V
PHV_INT_XA_G3H 0V
PP5V_G3S 0V

Readings in diode mode, positive probe in ground.
USBC_XB_CC1_CONN 815
USBC_XB_CC2_CONN 793
USBC_XA_CC1_CONN 805
USBC_XA_CC1_CONN 816

Resistance measurements (from ground to probe)
PP5V_G3S 25kohm and raising
PP3V3_G3S 0ohm (shorted?)

Other observations:
- I didnt see hints about liquid but there was some stuff and dirt around CD3215COOZ chips and battery chips. I cleaned them using isoprophyl alcohol and brush.
- Capacitor C7670 is missing. I found it detached (and lost it).
- U3100 (CD3215COOZ) feels warped - with finger it feels like there is slight bumb.
- Charger cable had yellow coloring in rubber and it looked like broken. Possible cause?
- When usbc-b is connected SYS_DETECT_LED blinks slowly.
- When usbc-b is connected SYS_DETECT_LED is constantly lit.
- No obvious hot spots detected using Flir heat camera. Allthough i'm not sure if the resolution is good enough.
- At first i measured battery at 11v but now it shows 10v.

I have feeling that CD3215COOZ chip replacement is typical case but is it here? I have read many forum posts, watched youtube videos and tried to understand how this works, but now I feel that I would really need some advice. Can you help me further?

[mon2]

Continue to use USB-C port since it can negotiate the PD contract for 20v.

What is the voltage to ground of P5VG3S_EN_DLY ? Some trouble here if the output rail is @ 0 ohms to ground. Checking if the enable signal is present for this power rail or not.

What is the voltage to ground of PPBUS_G3H ?

[Bogbog]

OK, here are the measurements:

P5VG3S_EN_DLY 0v
PPBUS_G3H 12.7v

Thanks for your reply, I appreciate it.

[mon2]

Try a DFU restore.

reference:
MacBook Air A1932 Not turning on, missing P5VG3S EN signal repair - Repair Wiki

Continue to post your updates here.

[Bogbog]

I managed to put device to dfu mode but both revive and restore actions fails. Device is titled as Apple controller in Apple configurator.

Progress bar stops at about 1/3 on step 4/4 Installing System.

Finally Apple configurator displays error message: "The system cannot be restore on this device. Gave up waiting for device transition from DFU state to DFU state. [com.apple.MobileDevice.MobileRestore - 0xFCA (4042)]"

I noticed that battery voltage raised from 10 to 11 when trying to restore. Apparently it is charging.

[mon2]

Try this:

https://boards.rossmanngroup.com/thr...2-error.64310/

[Bogbog]

I have tried dfu restore with two cables (Apple charger cable and high quality usb-c display- & charging cable)
- target battery disconnected
- target battery disconnected, target power connected
- target battery connected
- target battery connected, target power connected

Same result always, apple configurator hangs on step "4/4 Installing System". Host machine is 2018 MacBook pro with most recent MacOS.

[Tuxedo Gaming]

Hi bog bog, any updates on your MacBook? I find myself in a similar situation unfortunately. Additionally where can I find the schematics for the MacBook in question. I’d appreciate it if you could link it

regards