820-00281 19.5V 2.5A won't boot

ajdoc

Member
Small liquid on C6553

When all connected go 19.5V and 2.5A on charger.
No fan spin, no chime, trackpad no clicks.

PPBUS_G3H = 12.56V
PPBUS_HS_CPU = 12.56V
PP3V3_G3H = 3.41V
PPBUS_HS_OTH5V = 12.56V
PPBUS_HS_OTH3V3 = 12.60V
PPBUS_S4_HS_TPAD = 12.60V

PP5V_S5 = 5V
PP5V_S4 = 0V

PP3V3_S5 = 3.32V
PP3V3_SUS = 3.32V
PP3V3_S4 = 0V

PM_SLP_S5_L is missing.

Found a bit of liquid which gone under U1100.
Is there any point of re-hot of U1100?

Any hints?
 
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2informaticos

Administrator
Staff member
Trigger SMC_ONOFF_L and check for drop pulse at PM_PWRBTN_L (at same time).
If detected, check for pulse at PM_SLP_S4_L too.
 

ajdoc

Member
R1210/2 = 3.3V
R1210/1 = 0.36V

It got correct resistance 1K Ohms.

Removed shield from J9600 and there was liquid as well and pins 44, 4, 6 looks affected.
 

2informaticos

Administrator
Staff member
Be sure no corrosion between J1800 pads.

Low level on PM_PWRBTN_L should be caused by SMC, or PCH.
In your case, can be accumulated crap underneath BGA chips, or some corroded, or broken resistor/trace.
 

ajdoc

Member
Cleaned board in ultrasonic cleaner and on both sides of R1210 now got 3.3V

Board boot now but wont charge battery.
It shows 40% of charge so battery is visible by system but wont charge.

PPBUS_G3H without battery = 12.6V
PPBUS_G3H with battery = 11.6V

Is there any way to check if thats issue is on board or it need battery?
 

2informaticos

Administrator
Staff member
Always best to check with known good battery in such case.
You may waste the time, even cause more damage on MLB, when the culprit is the battery.
 
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