820-00165 Corrosion Near U3710 No Power

brunomotter

Member
Hello all. I got a board that was not powering on. After inspection I found corrosion around U3710. Put some flux on it, set my TR1300 station to 350 Celsius with medium airflow and gave it some heat. After 20 seconds or so the top layer seemed to pop and went back into position. I tried recalling the SMC and replacing it also, but still no green light. I have no shorts and PP3V42_G3H is present. PPBUS_G3H is 8.15V instead of 8.56V. I think that popped layer broke something internally to the board. Any way to verify that or the board is junk?
 

2informaticos

Administrator
Staff member
Remove first U7100.
If still the same, disconnect trackpad flex and test again.
If still low, clean/remove J6100.
 

brunomotter

Member
Correct me if I'm wrong, but by what I understood of what you told I should remove U7100 and plug in the board? Would't that fry the board because the lack of PWM control?
 

brunomotter

Member
It's out the case. Nothing but IO board and cable connected. Removed U5110 and still Low SMC_RESET_L, around 1,1V and going down up to 0.5V
 

2informaticos

Administrator
Staff member
So you had SMC removed from the board.
Did you check SMC_RESET_L level then?

Post now all U5110 voltages.
 

brunomotter

Member
U5110:

Pin 1 - 3.42V
Pin 2 - 0V
Pin 3 - 3.4V
Pin 4 - 2.77V
Pin 5 - 0V
Pin 6 - 3.42V
Pin 7 - 3.4V
Pin 8 - 3.4V

Diode:

Pin 5 - 0.003
Pin 8 - 0.523
 

brunomotter

Member
I replaced U7100, short gone and now I get orange light on charger(no green light though), but SMC_RESET_L still low near 0.9V
 
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