Macbook A2338 820-02020-A No power

[tommy97]

Hi guys,

I'm having problems with 820-02020-A, to start with macbook came with liquid damage, I cleaned the board, and it worked, however fan was on the full speed from the start. After while stop switching on, stuck on 5V 0amp draw.
PPBus_AON 1v
Replaced CD3217 - both as they were liquid damaged.
Replaced ISL
Checked current sense resistors next to ISL, values in order.
R5221 — 1.00 Ω
R5222 — 1.00 Ω
R5261 — 1.00 Ω
R5262 — 1.00 Ω

PP3v8_AON - missing as well _EN is missing
PPDCIN_AON_CHGR_R 5.17V

LDO's 5v
Checked all above - None of them are shorted.

[mon2]

What is the resistance to ground of PPBus_AON?

What is the voltage to ground of:

I2C_SMC_PWR_3V3_SCL
I2C_SMC_PWR_3V3_SDA

at the battery connector J5151?

[tommy97]

I2C_SMC_PWR_3V3_SCL - 0.03V
I2C_SMC_PWR_3V3_SDA - 0.03V

PPBus_AON on C5403 30M OHm and goes down.

[mon2]

Remove all power. Meter in resistance mode.

What is the resistance to ground of:

I2C_SMC_PWR_3V3_SCL
I2C_SMC_PWR_3V3_SDA

[tommy97]

Both are at about 4 M Ohm cycling up and down, checked on the 2nd board looks the same.

[mon2]

So no shorts here but missing the prerequisite / upstream voltages required to pull-up these open-drain lines.

With no power to the board, what is the resistance to ground of the following?

PPBus_AON ; measure @ F5200 (both sides of the fuse)

Next, flux and remove the fuse at F5200. Then power up again. What is the voltage now of F5200 pcb pad #1? Is it stable?

[tommy97]

F5200 - PPBUS_AON 0.8V (And goes down), PPVBAT_AON 1.065V Stable.
While fuse removed resistance on PPBUS 7M OHm and goes down on PPVBAT_AON 12M Ohm

[mon2]

With the fuse removed, power up. What is the voltage to ground at the pcb pad of removed fuse?

[tommy97]

PPBUS_AON 0.8V (And goes down), PPVBAT_AON 1.065V Stable. Those one are after fuse removed

[mon2]

Measure the voltage to ground of

PPDCIN_USBC_AON ; this is the input voltage rail to the ISL9240 (U5200) that creates PPBUS_AON

CHGR_AUX_DET ; at junction of R5215 & R5216

PP1V8_S2 ; @ C5280

[tommy97]

PP1V8_S2 ; @ C5280 = 0V & 2.5 k OHm

R5215 - PPDCIN 5V - CHGR_AUX_DET 1.2V
R5216 - 1.2V CHGR_AUX

[tommy97]

mon2 Have you got any idea for it?

[mon2]

With no load (no downstream fuse) and 5v as the power adapter voltage, the ISL9240 should enter boost mode and offer ~12v. If PD = 20v, then the ISL will enter buck converter mode and lower the input voltage to the ~12v output. If the current sense resistors are ok then suspecting the ISL to be defective. What does the visual inspection show? Was this chip replaced or reworked?

With no power, check the diode mode values against the attached.

[tommy97]

mon2 i've replaced once more ISL, and 12.28V come back however fan spin 100%, laptop power on and display.
I2C_SMC_PWR_3V3_SCL 3.3v
I2C_SMC_PWR_3V3_SDA 3.3v

UC710 - replaced / no change.
PPBUS_AON_3V3S2_VIN_ISNS 12.28V

[mon2]

Try a DFU:

https://repair.wiki/w/MacBook_Pro_A2...w_at_5V_repair