820-2850 dim green light on charger no powering up

[speedyaction]

i have board with was water damaged. replaced few components with was look bad but still no sign of life.:
PPBUS_G3H : 12.6v
PPDCIN_G3H :16.37v
PP3V42_G3H :3.41v
SMC_BC_ACOK_VCC: 3.42v
ADAPTER_SENSE: 3.42v
any idea why light is so dim and no power up ?

 

[JohnB8812]

Check voltage for PM_SLP_S4_L

 

[speedyaction]

PM_SLP_S4_L: 0.00v

 

[dukefawks]

Why check SLP_S4 when there is no green light? I'm sorry but stop giving advice when you still have to learn the basics.

STOP USING COMMENTS!

Green light is the first thing you need, tried a good magsafe board? Where was the corrosion?

 

[speedyaction]

corrosion was next to lvds connector and i replaced for new one. i try 3 different magsafe boards but still no luck

 

[dukefawks]

That can also means there is corrosion somewhere on the one-wire circuit. Possibly crap under the DCIN connector J6900. Check ADPATER_SENSE voltage and trace.

 

[speedyaction]

ok. i removed and clean dcin connector and bridged pin 5 dcin to u6900 pin 5 and now i have green light on charger but when i connect 16.5v charger. when i connect 18.5v no green light very strange situation

 

[dukefawks]

What is voltage on ADAPTER_SENSE with the 18.5V charger?

 

[speedyaction]

ADAPTER_SENSE when i connect 18.5v charger is : 2.89v

 

[dukefawks]

Too low, something is dragging it down should be 3V42. Bad magsafe board, crap under the connector, bad U6900. I assume SYS_ONEWIRE stays at 3V42 always.