820-01958-A no power after water damage

[blady313]

Hello,
I have a MacBook A2179 after a little water damage. Corrosion occurred on elements in a circle .


The current voltage is yellow, but I can't check it with clouds because I don't know where to measure it.

P5VG3S_EN is missing


















I am asking for help in diagnosing

 

[2informaticos]

You should post which signal/voltage missing from power on sequence.
Is dificil to understand what you mean with the diagram only.

 

[blady313]

all voltages / signals that I marked in yellow are present.

I cannot measure the voltage / signals on the little clouds because I don't know where to do it.


P5VG3S_EN is missing

 

[2informaticos]

Can you do DFU revive?
Be aware of restore option, that will erase entire SSD.

 

[blady313]

I tried many times but I can't put it in DFU.

How to Restore BridgeOS on a T2 Mac + Boot a Mac to DFU Mode

macOS Update brick your Mac? This article will show you how boot to DFU Mode and restore BridgeOS on a T2 MacBook Pro, Air, iMac Pro, Mac Mini & Mac Pro!

mrmacintosh.com

What can I do else?

 

[2informaticos]

If you get all SLPS2R and AWAKE voltages, it should enter to DFU.
If not there could be a problem with T2.

Be sure to have a good cable.
Test if you can access other T2 machine through DFU with the same cable.

 

[blady313]

Do I need the same MacBook model?
I don't know which system was installed od damaged MacBook.

The bridgeos is in T2 or spi chip?

 

[2informaticos]

You can connect with non T2 machine with Apple Configurator 2.
Just use the same macOS as in T2 machine.
If no sure which version is, then try with Catalina and Big Sur, maybe Mojave.

T2 has its firmware partition on internal SSD.
It should be detected in DFU, even if its partition is bad.

 

[blady313]

Host computer does not detect DFU I tried with 3 other original cables and 2 different macbooks with Catalina and big sur. This is a 2020 macbook, so it should be one of those systems.

Battery should be connected? or DFU can be working witchout the battery?

 

[2informaticos]

Should be detected without battery.
In fact, in DFU mode, USB-C port will stay in 5V.
Be sure to use the dedicated port in T2 machine.

BTW, someone in the forum reported a 2020 Mac Mini which came with Mojave from Apple.

 

[blady313]

I don't know what I do wrong.
Macbook host should has the same version of MacOS to just put another MacBook to DFU or I can put to DFU MacBook without any MacBook?
laptop host is necessary to put another laptop into DFU mode or can I put it without any macbook?
I check power button, it is ok.
Can I check that keyboard is working correctly?

 

[2informaticos]

Need to install Apple Configurator 2 in other MacBook, not necessary T2 machine.
Then connect both machines; follow the steps from that webpage.

I suppose something damaged by liquid spill.
Dificil to work without boardview.
Use 820-01521 as guide, but is not so close...

 

[blady313]

DFU doesn't work on this machine.
I can put in DFU another macbooks but not this one.

What can I do else?

I have just 3.3V.

 

[2informaticos]

You've said to have SLPS2R and AWAKE voltages.
If machine doesn't enter into DFU, then bad T2, or is affected by corrosion.

 

[piernov]

In theory you can force T2 to enter DFU by pulling SOC_FORCE_DFU to 1.8V.

 

[blady313]

where can I put that 1.8v? I found one place where can I do it, resistor R8010, do you know where is it?

 

[2informaticos]

I tried that in a rebel board (Air 01521) and didn't help; damaged T2, caused by liquid on audio board.
However, nothing to lose, just try it.

Force SOC_FORCE_DFU to 1V8_AWAKE with 1K pull-up.
Then connect the board alone to the other machine, trough corresponding USB-C port.

 

[blady313]

I understand but I don't know where can I connect resistor 1K, where on the motherboard is place where can I put this 1.8v

 

[blady313]

I had circuit on PP5V_G3S, U6500 was burned. I removed it and the short circuit is gone.

 

[2informaticos]

The board turns on now?