MacBook A2338 M2 (820-02773) Not Charging

[rounin]

Post:Hello everyone,I'm troubleshooting a MacBook A2338 M2 (820-02773) motherboard with a charging issue. Here’s the situation:Initial Fault:

• L8430 was burnt. After replacing it, the system worked normally for about two weeks, then failed to power on.

Current Symptoms:

1. Without Battery:
   • When connected to power, voltage ramps from 5V to 20V, then drops back to 5V, cycling repeatedly.
   • After disconnecting F5200, USB-C voltage stabilizes at 5V, and Pin 1 of F5200 measures 12V.
2. After Replacing U8100:
   • With the battery connected, the system powers on normally, and the battery icon displays correctly, but it does not charge.
   • Without the battery, the same 5V-20V cycling issue persists.
3. Replaced U5200:
   • Although I didn’t suspect U5200, I replaced it anyway. The issue remains unchanged.
4. Battery Test:
   • Tested with a known-good battery (verified on another working board), but the fault persists (no charging).

Measurements Taken:

• With power + battery connected:
  • I2C_SMC_PWR_3V3_SCL ≈ 2.78V
  • I2C_SMC_PWR_3V3_SDA ≈ 2.78V
  • SYS_DETECT_L = 0V
  • C5220 resistance ≈ 2.2Ω

Additional Info:

• No signs of water damage.
• I’m unsure where to check next.

Can anyone with experience offer suggestions? Could this be an SMC or other circuit issue? What key points or signals should I check? Any help is greatly appreciated!

[mon2]

Has the display assembly been replaced? Do you have True Tone? There was an issue earlier this year where the lcd assembly replacement will raise this fault.

[rounin]

Thank you for the help!

the display has not been replaced, and I don’t believe this issue is related to the screen.

When testing in a bare-board state (no display or other components connected), the power supply ramps up to around 19.5V (not quite 20V) and then resets, cycling back。

[mon2]

If available, inspect entire board with a thermal camera. Search for hot spots.

Remove all power. Meter in resistance mode. Measure the resistance to ground of each inductor. Suspecting you have a shorted part onboard. Post any low resistance inductors.

This is power cycling.