820-02100 M1 Pro Liquid damage

prodigy83

Member
My reference only: TT10141

Board history: Coffee spill. Most damage was around UP800, U5000, and U9300.
Issue: Not powering up, USB-C meter shows 4.92v, drawing .95 amps.
Work performed: Replaced U5200, Q5820, R5215, R5216, CW194, CW187. I removed and placed back down UP800, U9300, Q5240.
PP3V8_AON_SPMU is at 2.85v
F5200/01 is 7.4v. When I had removed these, USB-C meter reads 5.14v and drawing no amps. PPVBAT_AON_CHGR_REG with both fuses still removed has a stable 12.3v.
When I plug in the computer, the thermal camera shows half of the processor is getting warm, and U8100 is getting hot. I did also reflow U8100.
 

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prodigy83

Member
The filters are the LDO's?
U8100
PP3V8_AON_MPMU .070
PP1V2_S2 .284
MPMU_BUCK4_LX3 .069
MPMU_BUCK4_LX2 .069
MPMU_BUCK4_LX1 .068
MPMU_BUCK4_LX0 .068
MPMU_BUCK10_LX0 .147
MPMU_BUCK10_LX1 .147
MPMU_BUCK6_LX0 .452
MPMU_BUCK5_LX0 .272
MPMU_BUCK5_LX1 .274
MPMU_BUCK5_LX2 .273
MPMU_BUCK5_LX3 .273
MPMU_BUCK2_LX0 .433
MPMU_BUCK3_LX0 .343
MPMU_BUCK8_LX0 .284
MPMU_BUCK9_LX0 .245
MPMU_BUCK1_LX1 .327
MPMU_BUCK1_LX0 .327
MPMU_BUCK1_LX0 .231
MPMU_BUCK7_LX1 .231
MPMU_BUCK7_LX2 .232
MPMU_BUCK0_LX3 .208
MPMU_BUCK0_LX2 .208
MPMU_BUCK0_LX1 .208
MPMU_BUCK0_LX0 .208

U7700
SPMU_BUCK6_LX0 .217
SPMU_BUCK5_LX0 .066
SPMU_BUCK5_LX1 .066
SPMU_BUCK5_LX2 .066
SPMU_BUCK5_LX3 .066
SPMU_BUCK9_LX0 .446
SPMU_BUCK8_LX0 .259
SPMU_BUCK3_LX0 .259
SPMU_BUCK2_LX0 .325
SPMU_BUCK1_LX1.148
SPMU_BUCK1_LX0.148
SPMU_BUCK0_LX3 .221
SPMU_BUCK0_LX2 .221
SPMU_BUCK0_LX1 .221
SPMU_BUCK0_LX0 .221
SPMU_BUCK10_LX2 .103
SPMU_BUCK10_LX1 .103
SPMU_BUCK10_LX0 .103
SPMU_BUCK4_LX0 .086
SPMU_BUCK4_LX1 .086
SPMU_BUCK4_LX2 .086
SPMU_BUCK4_LX3 .086
 

prodigy83

Member
Yes, I saw the LDO's at the bottom of page 37 for chip U7700, but when I click on PP1V2_S2_SPMU for example, it goes no where as opposed when I click on PP3V8_AON_SPMU, it highlights all the capacitors around U7700. It doesn't appear openboard.org has this data either when I looked at a few.

U7700
PP3V8_AON_SPMU .070 this is off.
PP1V5_AON_VCORE_SPMU .383

U8100
PP3V8_AON_MPMU .070 is off
PP1V5_AON_VCORE_MPMU .382 No data on openboard.org.
 

prodigy83

Member
U7700
PP3V8_AON_SPMU 2.86v
PP1V5_AON_VCORE_SPMU 1.1v

U8100
PP3V8_AON_MPMU .070 2.87v
PP1V5_AON_VCORE_MPMU .382 1.10v
 

prodigy83

Member
How do I narrow it down? What are some possibilites? Should I Inject voltage even though it is not shorted to ground?
 

prodigy83

Member
Looks like it's the processor.
What is weird is I took up U5700 from the board and plugged the USB-C meter and I saw the voltage go to the regular 5.1v, but when using the IR camera, Q5840 got real hot, so I lifted this too, then Q5820 I noticed was getting quite hot. I put down some alcohol in this area and it was literally bubbling underneath the chip. Tracing the issue came back to P3V8AON_SW3. But injecting about 2.5v in to PP3V8_AON_SPMU, the processor lit up. I had plugged in my USB-C meter several days ago and saw the processor was heating up back then too.
Confirmation it is the processor?
 

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2informaticos

Administrator
Staff member
High side one can get open if its Gate floats on air.
As controller chip is no more soldered on the board, nothing can stop it to burn!
 

prodigy83

Member
Oh boy, okay, thanks, I now know. I figured I was safe if the chip is off. Total opposite, thank you for your help and knowledge.
 
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