a1989 5V 0,25A

[firebroker]

Hello, I am trying to repair my MacBook 820-00850 after small water damage. here are some facts:
USB-C port burned pin
liquid damaged pin on power button connector (
all ports stuck at 5V 0,25A, I can enter DFU (than 20V present and 0A), restore revive not working
I am missing all SSD power rail and enable signal SSD0_VR_P2V7_EN from U9000 too
L9080- diode reading is 0,4
L9080- right after unplugging charger is 0,078 and slowly rising to 0,4 (is it normal?)

can you advise me please ? thank you

[mon2]

Re: a1989 5V 0,25A

Check diode mode to ground of the LDO rails of all CD3215 chips. Post the readings.

Meter in diode mode.

Red lead (yes red) to ground.

Black meter lead to ldo rail to test.

Diode readings should be done after enough time is given to discharge the logic board.

[firebroker]

Re: a1989 5V 0,25A

thank you for your fast replay and time.
readings: pin 2, 35, 53, 75
U3100
0,493
0,527
0,515
0,534
U3200
0,497
0,529
0,517
0,535
UB300
0,498
0,530
0,518
0,537
UB400
0,496
0,529
0,518
0,534

PPBUS_G3H - 12,29V

[mon2]

Re: a1989 5V 0,25A

Diode readings look ok.

PPBUS_G3H - 12,29V

From:
https://www.logi.wiki/index.php?title=PPBus_G3H

This voltage is low and should be 12v6 after communication with the SMC.

Measure the voltage readings of:

I2C_PWR_SDA
I2C_PWR_SCL

which are level shifted I2C bus lines used by U7000 for communication.

Also measure the voltage readings of:

SMBUS_3V3_BATT_SCL
SMBUS_3V3_BATT_SDA

to confirm the status of D6950 (battery ESD transient protection device).

Meter in DC volts mode (anything 5 volts or higher is ok for these tests).

Black meter probe to ground (shield is ok).

Red meter probe to the point to test.

Post your readings.

[firebroker]

Re: a1989 5V 0,25A

I2C_PWR_SDA 1,79V
I2C_PWR_SCL 1,79V

SMBUS_3V3_BATT_SCL 3,36V
SMBUS_3V3_BATT_SDA 3,36V

Battery voltage is 0V
PPVBAT_G3H_CONN 12,6V after 4seconds 0,2V, after 4seconds 12,6V.. cycling

and see what happens
I have checked charger meter and suddenly 20V there and board started to boot. I assembled the whole machine back. I don't know what happened, but at the time of writing this post, MacBook started working... a miracle

Yesterday I did a reflow of U9000 and U9080 and did not help. I wrote here on Badcaps, did some measurement together and the board started to work now

Thank you very much for your time and help, If I can donate/support you, let me know please

[firebroker]

Re: a1989 5V 0,25A

And today the same problem appeard after nearly 10 days of active usage of macbook.
After few hours of youtube watching I wanted to charge a macbook and nothing happened.
20V 0A. Restart did not help, and then my battery went to 0% and is dead again
I am stuck at 5V 0,25A

SMBUS present, I2C present
any ideas for help ?
thank you

[mon2]

Re: a1989 5V 0,25A

What is the voltage of PPBUS_G3H ?

[firebroker]

Re: a1989 5V 0,25A

Ppbus_g3h 12,29v

[mon2]

Re: a1989 5V 0,25A

Review the diode readings of each LDO rail of the CD3215 as per post #2.

Remove all power. Meter in diode mode to measure.

One of the causes of being stuck @ 5V is that a CD3215 has failed.

[firebroker]

Re: a1989 5V 0,25A

it is still the same readings :/