macbook air m4 13" A3240 821-05409 5v

[yair37]

another air 5v case..this time is m4 13" water damage all the board look very clean, LDO ALL OK.
PPBUS_AON 12.2 STABLE
All the secondery voltage pulsing every few secound. no short no board.
CHGR_SYS_5V also pulsing.
CHGR_CSI_FILT_P 5v stable.

 

[2informaticos]

Isn't your board 820-03597?
However it is not available; what schematic using?

 

[yair37]

see it here:
The 2025 MacBook Air M4 (13-inch, Model A3240) logic board generally uses part number 821-05409-02. These M4 models (13" A3240, 15" A3241) feature soldered memory and SSDs, and they require a paired Touch ID sensor with the replacement board.

MacBook Air M4 (2025) Board Details:

• 13-inch (A3240): Board Number 821-05409-02.

But you right...the board is 820-03597 (Why don't they engrave on the board anymore).
Im using m3 board its very similar..so..

 

[2informaticos]

You still didn't post what 820-xxxxx schematic used for guide...

 

[yair37]

820-03285

 

[2informaticos]

Ask the customer, where the liquid was spilled.
Test the board alone, disconnecting anything else apart the charger.

 

[yair37]

On the keyboard, the Mac was work for a 2 weeks after that, and of course I was tasting it alone..

 

[2informaticos]

Also disconnected daughter board (keyboard interface)?

Should be good to test with known good battery.

 

[yair37]

Also disconnected daughter board (keyboard interface)? Yes of course and also try with a good battery but the same

 

[2informaticos]

3V8_AON pulsing too?

Check U5700's basic voltages; pins 8, 7, 5, 12.

 

[yair37]

3V8_AON 1.2v -0.7v (Dmode 180)

 

[2informaticos]

"Check U5700's basic voltages; pins 8, 7, 5, 12"
???

"Dmode 180"
Should be higher, I think; compare with working board.

 

[yair37]

i was replaced U5700 from macbook pro m1 14" and its work...thanks!