820-01598 liquid damage

[Blackmambo90]

Hello everyone!

I have 820-01598 board which had some small liquid damage.

The board does not boot, how ever aparrently it does charge the battery (the ams goes up when the battery is connected).

With the battery discconected, there is 20v@0.04amp and slowly goes to 0.01amp and to 0amp eventually

Was not ably to find ppbus voltage since dont have the schematics and bordview yet (any one have them by chance?) But there is 3.3v rail and 5v rail present on the board
There is also a rail with 9v that is present and there is 12v on battery connector.

The rest of rails are dead.

Any tips on this one?

 

[2informaticos]

Check if machine can be seen in DFU mode.

820-01598 - X1536.rar

drive.google.com

 

[Blackmambo90]

Thanks for schematic @2informaticos!

You were right, as soon as i plugged it to apple configurator, it saw it in recovery mode

However when i try to do the riveve, it fail with error 78 (no storage)
And i get error 9 when i try to do a restore

Does this mean the ssd is shot?

 

[Blackmambo90]

Edit: after a couple of try, it went as far as putting apple logo on to the screen with loading bar, but still fail with error 9 (no comunication)..

Usbc ports do look clean


Edit 2:

Okay, after trying a couple of times and with different cables, it finally finished the installation and booted to flashing folder
I took the power of to put the cover back and after i plugged it back, it still not boot and is still in recovery.

And when i try to restore it now, it give me error 47 failed to create filesystem and the screen stays at apple logo with the loading bar..

Any clues ?

 

[2informaticos]

You may have a problem with internal SSD.
Something still affected by corrosion.
Inspect the chips of SSD power rails.

 

[Blackmambo90]

The main liquide traces where around:
C4527, C4524, C4502, R3975, C4454,
U3750, U2021, C2021, U6641, C6641, C6642

And 5V rail: C6482, CD621, CD624, C7671, C7676
All look clean but will take another look tomorrow. However i tested all voltages on all those components (where it should be) and all looks good. I also look on voltages for ssd, all there as well...

 

[2informaticos]

Corrosion so clos to T2 is not a good sign.
Be sure all series resistors from its power rails are good.
Also check all pull-up resistors R397x.

Audio amplifiers are very sensitive to corrosion.
Can easy damage T2, because are powered from PPBUS_G3H.

 

[Blackmambo90]

Was going around the board once again today, and noticed that i am not sure if R6649 was there in the behuining, but its not there anymore
Any advice? (Look up the shamatics, but both of them seams to be there?)

 

[2informaticos]

Do you note liquid signs on audio board/flex?

 

[Blackmambo90]

No, and its give me the same error even if i disconnect everything from the board.
Going trought power pins on T2 chip, all seams fine except pin 136 SMC_PP3V3_WLANBT_ISENSE, THERE IS 0volt, not sure if its okay

Is there a list of voltages that i should look on ssd except PPnVn ?

 

[2informaticos]

Check SSD voltages, at L9020/30/80.

 

[Blackmambo90]

I am getting 0.9v on L9020, 1.8v on L9030 and 2.5v on L9080...

 

[2informaticos]

Good voltages.
Probably T2 solders, or some close components affected by corrosion.
Is also possible that some T2 data lines got damaged by liquid.

 

[Blackmambo90]

In that case the board is scrap?

Edit: if we think that the problem is ssd related, in that case why does the mac stay in recovery mode and does not boot to a flashing folder?

That lead me to belive that the issue is before ssd

 

[2informaticos]

You've reported an error about creating file system; it could be SSD related.
Another error, about communication, should be caused by T2 itself.

You can try to ultrasonic the board, or/and reflow T2 and other affected areas.

 

[Blackmambo90]

I tried to reflow T2 and there is no improvement.
Guess its scrap for good now since i cant find any more damages on the board.

When buying a used board "for parts", is it always activation locked?

 

[Blackmambo90]

Found that info on this cite:

"The SMC performs a Power-On-Self-Test (POST) to detect any EFI or hardware issues such as bad RAM and possibly redirect to Recovery"

And since it always stay in recovery, i presume the POST does not run as expected?
I guess i will recheck all voltages once again tomorrow to see maybe there is a missing one somewhere..

 

[Blackmambo90]

Update:

Mesured the voltage at coils just after the error message and when the screen is on with logo and frezed progress bar and found out that there is no power on L7702 (PPVCCEDRAM_PHASE)
Maybe thats why the post does not pass?
Any tips on what to look now? The resistance to ground is at 58om

 

[2informaticos]

Starting with S5, all voltages are controlled by T2.
These voltages are not involved in DFU.
If you cannot complete DFU, do not expect to get a correct power on sequence...

 

[Blackmambo90]

Had some time to play a little more with this one today.. apparently the issue is related to the ssd itself.. any thoughts about how to check it?