820-02020 water damage 5v ppbus pulsing.

[yair37]

water damage near UF400 clean all the area and replaced some damaged components and replaced UF400
5V 0.2A for 3sec and then 0.04A ppbus of F5200 12.3v pulsing. didnt see any short..

 

[2informaticos]

3V8_AON appears?
Check for pulse/short on master/slave LDOs.

 

[yair37]

3V8_AON - 3.8V
all LDO pulsing but no short..
USBC0_3V3LDO_EN_MUX 0V no short
USBC1_3V3LDO_EN 0v no short.

 

[2informaticos]

PPBUS/3V8_AON pulsing, or stable?
Master/slave LDOs on pages 28 & 33.

 

[yair37]

PPBUS 12.3v-8v pulsing
3V8_AON 3.8v stable
LDO Master:
PP1V4_LDO_PREREG 1.4v pulsing
PP1V5_VLDOINT_MPMU 1.5V stable
PP1V2_S2 1.2v pulsing
PP3V3_S2_UPC 3.3V pulsing
PP1V8_AON_ PMU 1.8v stable.

LDO Slave:
PPVDD_PMU_LDO_PREREG 1.4v pulsing
PP0V855_S2SW_CIO 0.8v pulsing
PP1V25_AWAKESW_VCCQ 1.2v pulsing
PP0V72_S2_VDD_LOW 0.7v pulsing
PP0V805_S1_VDD_FIXED 0.8v pulsing
PP1V2_AWAKE_PLL 1.2v pulsing
PP1V8_AON_SPMU 1.8v stable
PP1V2_S2_CIO 1.2v pulsing

 

[2informaticos]

Something else affected by corrosion on the MLB.
Check diode mode to ground on all coils.

 

[yair37]

Must be a short?

 

[2informaticos]

Can be, just check...

 

[yair37]

PP1V8_S2 0.0473 no full short, cant find from where the short. and im afraid to inject voltage

 

[2informaticos]

You should compare the reading with working board...

 

[yair37]

need to find one

 

[yair37]

PP1V8_S2 ongood board is 0.300

 

[2informaticos]

Then some component connected to 1V8_S2 is damaged...