820-00875 stuck at 19.3v no boot

[laptopcity]

Hi ive got an 820-00875 stuck at 19.3v no boot. ppbus_g3h is 12.93v pp5v_s5 is missing , diode reading is 450 on pp5v so guessing no short , i see it comes from pp5v_s5_ldo but cant find where that comes from, under the thermal cam the smc is getting hot . I did see the smc has pp5v_ldo but not sure if thats what im looking for . The board has reportedly had a spill but cant see any signs anywhere on the board or casing

 

[2informaticos]

Do you get SMC_PM_G2_EN?
Check U7800 (7 OF 10) output voltages, at page 60.

 

[laptopcity]

yes i get 3.3v on SMC_PM_G2_EN
PP3v_LDO3V = 3.3
PP5v_LDO5V =5v
PPBUS_PMIC = 12.96V
PP5V_S4 = 0V DIODE 430
PM_PGOOD_PVCCPCH = 3.3
PP3V3_S5 = 0V DIODE SHORT TO GROUND
PPBUS_G3H_CPU = 12.98V
PM_EN_P5VS4 = 0V DIODE 43PMIC_ALLSYSPGD = 0V DIODE SHORT TO GROUND
PM_EN_P3V3S4 = 0V DIODE 430
PM_PGOOD_P1V8 = 0V DIODE 485
PPBUS_PMIC = 12.96V
PP3V1_RTC = 0V DIODE SHORT TO GROUND
PP1V25_VREF = 1.24V

 

[2informaticos]

Post exact readings for "DIODE SHORT TO GROUND" above mentioned.

PMIC_EN_P3V3S5 comes on?

 

[laptopcity]

diode short readings 0 ohms on all
PMIC_EN_P3V3S5 at 2.3v

 

[2informaticos]

Do you mean to have 0 ohm to ground on all these coils???
I hope you've disconnected power first.

 

[laptopcity]

sorry PM_EN_P5VS4 is 499 in diode mode (measured in the wrong place sorry ) but yes the other 2 are o ohm to ground (without the power supply )

 

[2informaticos]

Bad CPU, or U7800.
Lift L7690 one side and see where the short remains.
You can use voltage injection method, to find the culprit.

 

[laptopcity]

ok thanks for your help

 

[laptopcity]

just for reference if it helps anyone it was a bad cpu :-(