820-3476 PP3V3_S0 got only 1.78V, missing PM_SLP_S4_L

[ajdoc]

Hi Guys.

820-3476 no liquid damage.
I know client had fake charger.

Got light on charger but no fan spin.

PP5V_S5 got 5V
PP5V_S4 got 0V
PP5V_S0 got 0V

PP3V3_S5 got 3.3V
PP3V3_S4 got 0.46V
PP3V3_S3 got 0.46V
PP3V3_S0 got only 1.78V

U8030 pin 6 which is P3V3S0_EN got 0V.

I I good understand PP5V_S$ is created by U7501 and Q7520.

Q7520/1 @12.5V
Q7520/3 @0V
Q7520/4 @0V
Q7520/5 @0V
Q7520/6-8 @0V

U7501/2 @0V
U7501/4 @0V
U7501/5 @0V
U7501/14 @5V
U7501/20 @3.34V
U7501/21 @3.41V
U7501/23 @12.56V

P5VS4RS3_EN @0V
PM_SLP_S4_L @0V

I know PM_SLP_S4_L is created by U0500.
Cant find any corrosion on input lines of U0500 like PM_PCH_PWROK, PM_PWRBTN_L etc.

Any idea what next? Is there is chance CPU is fried? Dat have light on USB.

 

[2informaticos]

Do you get 3V3_SUS?
Check PM_BATLOW_L, PM_RSMRST_L and PM_PWRBTN_L.
Also check all PCH's RTC signals.

Trigger SMC_ONOFF_L and check for reaction (drop pulse) at PM_PWRBTN_L.
If yes, check if any PM_SLP_Sx_L signal pulses at least (at same time).

 

[ajdoc]

3V3_SUS @3.34V
PM_BATLOW_L @3.1V
PM_RSMRST_L @3.26V
PM_PWRBTN_L @3.41V

?SMC_ONOFF_L and check for reaction (drop pulse) at PM_PWRBTN_L.?
Yes, there is drop to 0.34V

PM_SLP_S4_L pulse from 0V to 1.1V

RTC signals:
PPVOUT_S0_PCH_DCPRTC 1.58V
PPVRTC_G3H 3.34V
PCH_CLK32K_RTCX1 0.375V
RTC_RESET_L 3.32V
PCH_SRTCRST_L 3.32V
PCH_INTVRMEN 2.90V
PCH_INTRUDER_L 2.54V on that line there is R1301 which should have 1M resistance but got 0.860M

 

[2informaticos]

If PM_SLP_S4_L pulses, all S3 voltages should pulse too, check that.
Change "x" and check the other signals and corresponding voltages enabled.

ALL_SYS_PWRGD pulses?

 

[ajdoc]

There is pulse on:
PP3V3_S3,
PPVTTDDR_S3,
PP1V35_S3,
ALL_SYS_PWRGD

PM_SLP_S5_L very small pulse
PM_SLP_S4_L pulse
PM_SLP_S3_L pulse
PM_SLP_S0_L no pulse

 

[2informaticos]

"PM_SLP_S3_L pulse"
It controls some S0 voltages; did you check them for pulse?

Check for pulse at pins 1 & 3 of U1950.