820-01041 no boot, liquid damage.

[Zeifurhugen]

Hi, first time poster, thank you for everything you guys do here.

I have 820-01041 that had water spilled through the keyboard. The visible damage/corrosion on the Logic Board was minimal.

The only visible damage was located around the CPU/GPU Phase chips (U7220, U7230, QA340).. again very minimal, small amounts of white corrosion/oxidation.

All ports show 20v with 0A draw.

The only thermal activity on the board is the T2 and corresponding charging chips warming up.

PPBUS_G3H - 12.6v
PPBUS_HS_CPU - 12.6v
PPBUS_HS_GPU - 12.6v

PPVCC_S0_CPU - 0v
PPVCCSA_S0_CPU - 0v
PPVCCGT_S0_CPU - 0v
PPVCCIO_S0_CPU - 0v
*Resistance measurements match good board on all CPU lines listed above*

PP1V2_S3 - 0v
PP1V2_S3_CPUDDR - 0v
PP1V2_S0SW - 0v

PP1V8_G3S - 1.8v
PP5V_G3S - 5.1v
PP3V3_G3H_T- 3.3v




Please note the following:
1. I have tested all the lines that show up as 0v for shorts to ground and all line readings match good board.
2. I attempted T2 revive after cleaning visible corrosion and I get error code 4010, the fans go full speed after failed T2 revive.
3. I replaced U7210, U7220, U7230 and attempted T2 revive again and it still failed with 4010 and I still get 0V on all CPU rails
4. I understand board may fall into the "brain dead" category, however I want to cover all my bases and learn potential additional troubleshooting methods I could apply in this situation. It feels like the board should be repairable as the liquid damage was visibly very minimal.

Thank you for your time.

 

[2informaticos]

First of all, welcome to the forum!

Can look as minimal, but liquid on the CPU power supplies can be letal!

Do you get 3V3_S5?
Check if all SSD power rails are good.
Keep in mind, T2 and Touchbar have dedicated partitions on the SSD.
SSD voltages must appear very soon on T2 boards.

 

[Zeifurhugen]

Thank you very much for the response.

3V3_S5 is 1mv - I checked for short to ground and the line has a normal diode reading. Looks like U7800 creates 3V3_S5?

0v9 NAND - 0.9v
1v8 NAND - 1.8v
2v5 NAND - 2.5v

 

[2informaticos]

Do you know which macOS version is on T2 machine?
Apple Configurator 2 MUST be executed on the same version.
You can try DFU from Catalina, as Big Sur too.
We have a good tutoeial linked on the forum...

 

[Zeifurhugen]

Yea, I tried T2 revive on Catalina and Big Sur, I get the same error 4010. Thanks!

 

[2informaticos]

Try using another network connection.
Disable router firewall.

 

[Zeifurhugen]

Same result, also not sure if it matters but I have successfully revived many T2's on my main internet connection. Thanks again.

 

[2informaticos]

You can try to reflash U4770 (SoC ROM).
Need a dump from other similar board.

 

[Zeifurhugen]

Hi thanks again for your support.

I now have a ROM reader, I have a good ROM dump from a good A1990.

Is the data at jeopardy if the ROM dump has the wrong serial number/UUID?

Thanks again.

 

[2informaticos]

Try and see what happens.
I cannot confirm that is a problem caused by the SoC ROM however.