820-00923 USB-C don't work

[iClub]

Hi, this mac had liquid damage and came with oxidation on the USB-C controllers on one side (U3200 and U3100). I did a cleaning but it was not successful. When I made measurements in reverse diode mode on the LDO signals, on all four controllers, I got:

U3200
PP1V8_UPC_XB_LDOD: 0.466V
PP3V3_UPC_XB_LDO: 0.517V
PP1V1_UPC_XB_LDO_BMC: 0.495V
PP1V8_UPC_XB_LDOA: 0.501V

U3100
PP1V8_UPC_XB_LDOD: 0.469V
PP3V3_UPC_XB_LDO: 0.517V
PP1V1_UPC_XB_LDO_BMC: 0.499V
PP1V8_UPC_XB_LDOA: 0.503V

UB400
PP1V8_UPC_XB_LDOD: 0.465V
PP3V3_UPC_XB_LDO: 0.517V
PP1V1_UPC_XB_LDO_BMC: 0.495V
PP1V8_UPC_XB_LDOA: 0.502V

UB300
PP1V8_UPC_XB_LDOD: 0.471V
PP3V3_UPC_XB_LDO: 0.517V
PP1V1_UPC_XB_LDO_BMC: 0.504V
PP1V8_UPC_XB_LDOA: 0.509V


Next, I replaced U3200, Q3200, U3100, Q3100 (because they were oxidized too much initially) and also UB300, for presenting slightly altered values compared to the other chips.
The board turns on and the system goes up, but as initially, it does not show any activity in any of the four ports, and the keyboard does not work (probably because of the liquid, although I have not tested another). I can't get past the user login screen, because I can't type the password (because of the keyboard) and I can't use an external keyboard, because none of the four ports work. Sometimes, even on this screen, the machine restarts by itself and apparently generates an error report, but I can't see it because it is not possible to access the system.

Can you help me with what measurements I should take? Thanks!

 

[2informaticos]

So actually machine powers up with all four USB-C ports, but none of them has USB activity?
Do you get 5V at corresponding coil, L3500, or LB700?

 

[iClub]

No, the machine will not power up when plugging the charger into any of the ports. I could only turn it on because the battery still has charge. L3500 and LB700 both have 0V (even connected to the charger)
When I plug in the charger, without connecting the battery, I get:

PP20V_USBC_XB_VBUS (corresponding to the one I connected): 5V

PPBUS_G3H: 0V

 

[2informaticos]

Check U2890, adjacent resistors and traces.

L3500, or LB700 must get voltage only when USB device is detected on the corresponding port.

 

[iClub]

U2890 and surrounding resistors are in good condition, also with good resistance values according to the schematic.

Voltage values of the U2890's lines:

TBT_X_SPI_CS_L: 3.37V
TBT_X_SPI_MISO: 3.37V
TBT_X_ROM_WP_L: 3.37V
TBT_X_SPI_MOSI: 0.4V
TBT_X_SPI_CLK: 0V
TBT_X_ROM_HOLD_L: 3.37V
PP3V3_UPC_XB_LDO: 3.37V

 

[2informaticos]

I bet for more corrosion problems in USB-C areas.
Can't be other reason, if the board works on battery.