820-00923 Liquid damage on CPU Phase Mosfets - 20V 0.02A

[it-solve]

Hi Folks,

Got this 13MB which had a liquid spillage mainly around U7410/C7413 and U7210, everywhere else is OK on the board. After clean I get 20V, but no other response.

When USB controller chips seem to be ok, where do we start from?

PPBUS_HS_CPU - - 1.2Ohm seems to be affected via PPBUS_G3H or vice versa
PPBUS_G3H - Short to the ground - 1.2Ohm on the R6907 side of the F7000
As there are so many places this can be is it safe to inject up to 13V here?

Thanks

 

[it-solve]

Alright, replaced U7210 as a cause for the G3H short, and now turns on. Fans spinning with no picture.

I am still missing CPU PH1/2/3 voltages on L7410/20/30

What controls them?. U7410 had heavy liquid but has no short. Can PH1 being down brought others down too? Or would they still provide voltage if U7410 is faulty?


Edit:
Out of nowhere after, I replaced U7410 my 20V is gone down to 5V.
Seems like PP3V3_UPC_XB_LDO / PP1V8_UPC_XB_LDOD are having a short. With no liquid or oxidation in the area whatsoever.

PP3V3_UPC_XB_LDO - 0.0057Vdc
PP1V8_UPC_XB_LDOA - 0.519Vdc
PP1V8_UPC_XB_LDOD - 0.03Vdc
PP1V1_UPC_XB_LDO_BMC - 0.55Vdc

Lifted up C3208 same readings. What are the odds U3200 to pack up at the same time as U7400 replacement :/

XA_ U3100 readings seem to be ok. No shorts there.

These USB-C controllers are with underfill. What is the best way to get it cleaned?
Measuring remaining ones seems okay, and this one is the one which pulls less current than other 3. Must be bad?

 

[2informaticos]

PPVCCGT_S0_CPU only appears under high graphics load.
You screwed up something else on the board.
Do NOT make more wrong assumptions on the future...

You've only checked for video before, didn't think to check USB activity?

Did you inject voltage on PPBUS_G3H to find hot U7210?

 

[it-solve]

I wonder how U3200 got affected.

Forgot to mention that, I have Injected 1.2V on PPBUS_G3H and noticed CPU start increasing heat. From there I suspected U7210 being short.

There were no USB activity or external video when fans were spinning.

Thanks for your reply.

 

[2informaticos]

1.2V shouldn't affect CPU, but do NOT inject again in such manner.
So many time I explained how NOT to inject voltage on PPBUS_G3H and people still do this .

U7210 could already damaged CPU, when got burnt.
Do not expect too much from this board.

Probably the heat applied on the board affected USB-C area...

 

[it-solve]

Thanks for that.

You are absolutely right, haven't seen these treads though. Perhaps a sticky post with common mistakes we have learned will be great.

I got excited when the fans spun up, but there was no activity anywhere else. Does dead CPU allows fans to spin up?
Perhaps it doesn't worth changing U3200 and digging more if dead cpu would show such signs.

I am really after the data on this board, it has a J9600 but I still cannot justify buying the data migration tool due to amount of data recovery jobs I get for these couple compatible models.
Have you seen any other way of getting data out?

 

[2informaticos]

Get the board working, or the data migration tool.

Sometime internal SSD can be accessed starting on Target Disk mode, but depends of the fault problem on the board.