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A2442 after liquid damage

A

adrko

Member
Device was liquid damaged
Unfortunately it supposedly was in 2 repair shops prior and has signs of a diy attempt.

Nothing too serious though.
It was probably "tested" and supplied power while missing 3 bigger and 1 small caps on PPVIN_P3V8AON_ISNS line, in Q5800 and Q5820 vicinity

After replacing corroded and missing components around Q5800 it was taking 5V with 0.9 amps.
U8100 was heating up and I noticed a bulge/delamination on the very left edge, in the middle.

My guess it was at PP3V8_AON_MPMU_ISNS pads.

After replacing U8100 I get 5V and 0-0.6 amps. On the thermal cam I see L8239 (MPMU_BUCK3_LX9) power cycling very fast.

When I decided to test in the housing I got 19-20V briefly, I disconnected power right away to connect everything and test, because I thought I fixed it.

After investigating other power lines I discovered that:
PPBUS_AON - 10-12V unstable
PP3v8_AON - 3.8V - stable
PP5v_S2_MAIN 1.6 - 3.3V - unstable.

Battery connected or disconnected - no changes.
No changes when using magsafe instead of USB C

Decided to replace U5700 and U5200

Nothing has changed.
Need assistance, any advice would be appreciated.
 
A

adrko

Member
PPBUS_AON fluctuating on the desk without anything connected
U8100 LDO:
VIN_LDO - PP3V8_AON_MPMU_ISNS - 3.8V stable
PP3V3_S2 - 0.7-2V - cycling
PP1V8_S2SW_CLVR_VDDC1_LDO - 0.7 - 0.8 - 1.8V - cycling
PP3V3_AON - unstable
PP0V8_S2_CLVR_VDDDIG - 0.34 - 0.60 - 0.79V - cycling

PP1V8_AON - 1.8V stable
PP1V2_AON - 1.20V stable
PP1V5_AON_VCORE_MPMU - 1.50V - stable


U770 LDO:
PP1V2_S2 - 0.3 - 0.6V - cycling
PP1V8_S2 - 0.1 - 1.2V - cycling
PP3V8_AON_SPMU_ISNS - 3.79V - stable
PP0V72_S2_VDDLOW - 0.4V - cycling/unstable
PP1V2_AWAKESW_BLC - 0V
PP1V8_AON_SPMU - 1.79V - stable
PP1V2_AON_SPMU - 1.2V - stable
PP1V5_AON_VCORE_SPMU - 1.49V - stable
..
 
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