820-00138 - No green Light

[kronos23]

Hi guys.
Working on a 820-00138 board with liquid damage. No green light on adapter.
Cleaned up and replaced U5110 and surrounding components.
PPBUS_G3H - 12.26v
PP3V42_G3H - 3.409v
SMC_BC_ACOK_VCC - 3.409v
SYS_ONEWIRE - 3.387v

Made sure I am using original 85w Magsafe 2 however I only get 16.73v on f7005 both sides. shouldnt it be 20v ? I am also testing with a known good magsafe board.

U7100 - Pin 17/18 - 2.9 Ohm
U7100 - Pin 27/28 - 20.9 Ohm

Thanks.

 

[aprendiz]

Check if SMC_RESET_L is high, if yes, seems to be a bad SMC...

 

[dukefawks]

SMC not running. SMC_RESET should be high. Corrosion under SMC likely, reflow before replacing.

 

[kronos23]

SMC_RESET is 0.006 so dead SMC. Reflowed didn't work.

 

[MDY]

You need 3V for smc_reset. Check where this signal is created. This doesnot mean dead SMC.

 

[dukefawks]

Corrosion on J6100, remove it. R5100 checked? Resistance to GND on SMC_RESET?