820-4924-A Doesnt turn ON

[MaxFix]

Hi there,

Was water damage but not too bad. After ultrasonic clean:

PPBUS_G3HOT -12.5V
PP3V42_G3H - 3.5V
PP5V_S3 - 0V
PP5V_S0 - 0.3V
S5_PWRGD -3.4V
SMC_ADAPTER_EN - 0V
PM_SLP_S4_L - 0V
PP5V_S5 - 0V
PP3V3_S4 - 0V
PP3V3_SUS - 0V

Corrosion was on:
U5110
C5120
C5127
R5127

Please advice how to proceed. Thanks!

 

[dukefawks]

ADAPTER_EN should be high of course. Using a 60 or 85W charger? SMC_RESET high? Green/orange light present?

 

[MaxFix]

No light on Magsafe. No ADAPTER_EN, no SMC_RESET.
U5110 pin 1 - 3.42V.
Using good old apple magsafe 1 85W with dual output: 18.5V 4.6A and 16.5V 3.6A but also tried with 60W Magsafe just in case

 

[smiba]

SMC_ONOFF_L high? SMC_MANUAL_RST_L high? R5100 within specification?

If yes to all, I'd say replace U5110

 

[dukefawks]

If SMC_RESET is not high then PPBUS can never be 12.5V, it will be 12.3V. Also you have no green light so why did you even measure anything after that?
U5110 issue, R5100 corroded or crap under SMC.

 

[MaxFix]

Correct. PPBUS is 12.3V.
Replaced U5110. One leg was corroded.
Got orange light on MAgsafe but still no SMC_RESET or Adapter_EN.
Put contact cleaner under SMC. Then ultrasonic it. Then pressure air. Dry. Test. No Luck. Reflow with flux. No luck. No more orange on Magsafe.
SMC_ONOFF_L high
SMC_MANUAL_RST_L low
R5100 replaced because was off but now in right value.
SMC?

 

[dukefawks]

Pull SMC and see if SMC_RESET comes high.

 

[MaxFix]

Pulled SMC but still 0V SMC_RESET.

 

[dukefawks]

U5110 or pull up resistor then. There is not much more to this circuit. Check voltages on U5110