820-3476 Water Damaged, S4 Rails Missing

soulsby29

New member
Hi,

I have a water damaged 820-3476. Initially it was turning on but after a minute or so would keep going into hibernate/standby mode. Now however it is not even turning on but does have a green light on the charger. Testing the board voltages for S5 rails are present but not for S4.

PM_SLP_S4_L is 0.195 volts
ALL_SYS_PWRGD is 0 Volts

I am a bit unsure where to go from here.

Thanks
 

dukefawks

Administrator
It should get a green light and then orange without battery connected. Is SMC_LID high? Where was the liquid damage?
 

soulsby29

New member
Yeah I get a green light then it goes orange. Most of the water damage was around the connector for the keyboard backlight and the Mic connector. Everywhere else looking under a microscope doesn't seem too bad. I get 3.3 Volts at SMC_LID and in diode mode it measures 0.438.
 

dukefawks

Administrator
Could be anything. Inspect for corrosion around the usual suspects, U1900/U1950, U6100 and traces/termination resistors, crap under SMC. PPVRTC present?
 

soulsby29

New member
I have checked all these and there is no evidence of water damage or corrosion. PPVRTC is 3.3 volts. I am obviously missing something but I can't figure it out.
 
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