A2442 - 820-02098A 5V 3mA-0mA

[jadao]

Got this board for repair, 5V 3mA for a couple of seconds then 5V 0mA. it had a tiny spot of liquid damage on C7768 (PP1V2_AON_SPMU pad corroded gone ) and C7780 (PP1V5_AON_VCORE_SPMU pad corroded gone).

PPBUS_AON: 12.29v
PP3V8_AON: 3.8v
PP3V8_AON_MPMU_ISNS: 3.8v
PP1V2_S2: 0V / 0.231

PP3V3_S2: Unstable 3.3V to 1.25V / diode mode value: 0.376
PP1V8_S2SW_CLVR_VDDC1_LDO: Unstable 1.8V to 0.5V / diode mode value: 0.492
PP3V3_AON: Unstable 3.3 to 0V / diode mode value: 0.375
PP0V8_S2_CLVR_VDDDIG: Unstable 0.8V / diode mode value 0.289
PP1V8_AON: 1.8V
PP1V2_AON: 1.2V
PP1V5_AON_VCORE_MPMU: 1.5V

PMU_VDDHI: 2.584V

I replaced U8100 from same donnour board and I got exactly same results...
I compared coils diode value around U8100 and U7700 with donnour board and they are the same. I also see no voltage on any coil around u7700.

Damage affected 2 signals PP1V2_AON_SPMU and PP1V5_AON_VCORE_SPMU coming right from U7700, but I have no way to test them for shorts because pads are gone on the filter capacitors...

 

[2informaticos]

The corrosion was near the SPMU, not MPMU.
Why changed U8100 then?

 

[jadao]

You are right, despite liquid damage was exactly on the other side of SPMU board, I thought PP3V_AON unstable must have to do with (mpmu) U8100. I should have asked before.
Now I am exactly at square one, I was going to replace spmu but wanted to ask if any other conditions to check before reballing a replacement one…
Thks