Macbook Air M1 a2337 - 820-02016

[obelix24]

I'm working on Macbook air a2337

It's stuck on 5V.

I've replaced both CD3217B12 IC's and U8100

When i connect USB-C ampmeter i'm getting 5V 0.01 - 0.4a and restart ampmeter and again ....

I tried to connect to another mac and i'm not able to get it to DFU.

history is that this macbook just died randomly and owner was not able to start it again.

PPBUS_AON is 12.3V
i'm missing PP5V_S2 - 0V

According to repair wiki i've checked https://repair.wiki/w/MacBook_Air_A2...a_at_5V_repair

I can see there is heatspot at U0500.

Any idea how to proceed ? I don't have another donor board (a2337) but i have 2x a2338 (macbook pro) they i hope have lot of same components.

[mon2]

Remove all power. Meter in resistance mode. What is the exact resistance to ground of PP5V_S2? Being 5v - could be related to a USB VBUS failure.

What is the voltage to ground of P5VS2_EN? This is the enable signal for the same power rail.

[obelix24]

PP5V_S2 - resistance to ground 5M(mega) ohms and falling down

P5VS2_EN - resistance to ground is OL

[mon2]

Do you have a voltage on P5VS2_EN ?

[obelix24]

yes when power is connected and testing on test point next to RC333 there is 1.8V

I just noticed strange thing.

When power is connected to bottom (DFU port) here it's restarting ampmeter and here I have 1.8V on PP5S2_EN
but when I connect power to the other port there is 0V on PP5S2_EN and ampmeter is not restarting

[mon2]

When there is an ENABLE signal to this regulator, do you see a voltage @ PP5V_S2? If not, suggest to replace UC300 which may be defective.

Replace with the exact same part (Aliexpress):

LT8642EV-2#PBF

[obelix24]

Is it not possible that one CD3217 is defective ? as one port it restarting ampmeter (there is 1,8V on PP5S2_EN) and second port is stable 5V (not restarting ampmeter) but here i have 0V on PP5S2_EN ?

Or this can be related to UC300 ?

[obelix24]

i tried to replace UC300 from a2338 but it's behaving same (one port restarting, other stable both 5V)

[mon2]

Replace the port controller that is power cycling:

https://logi.wiki/index.php/CD3217_a...er_on_Sequence

[obelix24]

I tried to replace CD3217 3x and it's still doing the same (restarting) I also replaced U0500 as it's the only thing pulsing but also it's still the same and there is still hotspot on U0500

I've checked diode mode on U0500 and they're all looking ok

PP1V8_AWAKE - 0.319
I2C_SEEPROM_SCL - 0.323
I2C_SEEPROM_SDA - 0.323
P1V25_AWAKE_IO - 0.263

[obelix24]

Is it possible that M1 is dead ?

I'm checking values from : https://repair.wiki/w/MacBook_Air_A2...a_at_5V_repair

• Check for shorts to ground on outputs of U8100 and U7701: How to find short circuits
  1. L8100 / L8101 / L8102 (PPVDD_PCPU_AWAKE) (Figure 1) - Normal diode mode to ground reading ~0.007 / ~45Ω (Resistance)
  2. L82B0 / L82B1 (PPVDD_ECPU_AWAKE) - Normal diode mode to ground reading ~0.114 / 140Ω (Resistance)
  3. L8270 / L8271(PPVDD_CPU_SRAM_AWAKE) - Normal diode mode to ground reading ~ 0.116 / 450Ω (Resistance)
  4. L8120 (PPVDD_SOC_S1) - Normal diode mode to ground reading ~ 0.012 / 110Ω (Resistance)
  5. L8110 / L8111 / L8112 (PPVDD_GPU_AWAKE) - Normal diode mode to ground reading ~ 0.010 / 35Ω (Resistance)
  6. L8280 / L8281 (PPVDD_DISP_S1) - Normal diode mode to ground reading ~ 0.055 / 233Ω (Resistance)
  7. L8290 (PPVDD_DCS_S1) - Normal diode mode to ground reading ~ 0.176 / 310Ω (Resistance)
  8. L84E0 - (PP1v4_LDO_PREREG) - Normal diode mode to ground reading ~ 0.285 / >30kΩ (Resistance)

And I have different values
L8100 - 28.6 ohm / 0.044
L82B0 - 107.5 ohm / 0.198
L8270 - ohm not measurable it's jumping between kilo ohms, ohms megohms / 0.271
L8120 - 26.2 ohm / 0.043
L8110 - 24.8 ohm / 0.046
L8280 - 143.5 ohm / 0.208
L8290 - 220.5 ohm / 0.277
L84E0 - 1.6 M ohm /