820-3437 no green light/power or SMC_RESET_L

ytesfay80

Member
This board was liquid damaged in many places including the SMC.
Here are a list of the components I replaced:
U5110 - C5120
Removed JTAG (J6100)
U7090 - L7095 - C7098/99
R5501/2 - Q5500/10 - R5511/12
U1950 + C1950
C5020 & R5100 (Around SMC)

I am getting 16.6V on PPDCIN_G3H and into the U7090 chip. There was a short on Pin 2 of L7095(PP3V42_G3H) and I tracked it down to the U5110 so I replaced it and the short was gone.
For some reason though when I measure PP3V42_G3H I only get around 0.9v but as soon as I touch Pin 1 of L7095 PP3V42_G3H goes to around 4.6v. When I initially plug the charger in Pin 1 of L7095 usually shows voltage anywhere from 4.3v to 4.6v and one time it showed 3.1v.
Pin 1 of L7095 is almost always around 4v when I measure after plugging in the charger. Pin 2 of L7095 usually fluctuates around 0.91v to 1v when I initially measure but as soon as I touch Pin 1 and measure again it jumps to around 4v. I have never seen this issue where Pin 2 is a certain voltage and it changes once Pin 1 is touched.

I get 0v on SMC_RESET_L and I figure that is because PP3V42_G3H is not a steady 3.42v. Could it be that the U7090 chip I replaced with is bad as well?

Diode mode of L7095 - 0.35v
Diode mode of SMC_RESET_L - 0.47v
 
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ytesfay80

Member
UPDATE: I replaced C7095, R7095/6 and the U7090 chip again and now I am no longer getting any voltage on L7095 and in diode mode L7095 is 0.295v
Here are the voltages from the U7090 chip:
Pins 1,2,4,5 -0v
Pin 3 - went from 0.21v slowly up to around 0.36v
Pin 6 - 16.4v
Pin 7 - starts around 7.4v and slowly goes down to around 7v
Pin 8 - 16.55v

Update #2: I ultrasonic'd the board and afterwards I plugged the charger in and the light showed orange but it looked slightly dim and it never came green at any point. I unplugged the charger and plugged it back in and now there is no light when I plug the charger in.
The voltages are the same as above except Pin 7 is 0.6-0.8v and Pin 3 is 0v.
 
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dukefawks

Administrator
Probably bad SMC to start with pulling down 3V42. You can inject 3V42 and see if anything gets warm and if green/orange light works.
 

ytesfay80

Member
Okay I injected the voltage on Pin 2 of L7095 then plugged the charger in but still no light on the charger. I got 3.4v on SMC_RESET_L but on Pin 14 of U7100(SMC_BC_ACOK) it was 3.21v. Pins 13 of U7100(CHGR_RST_L) was around 3.4v also.
 
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