[SOLVED]820-3208 - Turn on if i press and hold power button.

[RedDemonic]

not liquid damage, cant see any corrosion at all under a microscope (damn it). never been rework.

Using a ?Real Genuine Original Apple Charger!

green light, orange light, can charge the battery?.

if I press and hold the Power Button for 2-3 second, the board will power up to OSX and fan spin normal
if i press once, the fan will spin for 1 second and failed.

Yes, the board is out of the housing, without the trackpad plugged in.

ASD shows 12 sensors has failed.

PPBUS_G3H = 8.39v
PPBUS_S5_HS_COMPUTING_ISNS = 8.38v
PPBUS_S5_HS_OTHER_ISNS 8.36v
PPVRTC_G3H = 3.3v
PP5V_S5 = 5.13v
PP3V3_S5 = 3.3v
PP3V3_S4 = 0.007 (i get 3.3v for split second if i replug the magsafe)
S5_PWRGD = 3.4v
PM_SLP_S4_L = 0v. (i get 3.3v for split second if i replug the magsafe)
P5VS3_EN = 0v (i get 3.3v for split second if i replug the magsafe)
PP5V_S3 = 0v (i get 5.1v for split second if i replug the magsafe)
PP3V3_S3 = 0.023v (i get 3.3v for split second if i replug the magsafe)
PP5V_S0 = 0.02v (i get 5.12v for split second if i replug the magsafe)
PP3V3_S0 0v (i get 3.3v for split second if i replug the magsafe)
PP5V_S5 - 0v (i get 5.1v for split second if i replug the magsafe)

ALL_SYS_PWRGD = 0.0v
SMC_PM_G2_EN = 3.421v
SMC_BC_ACOK - 3.394

 

[RedDemonic]

17/18 : 2.8 ohms
27/18: 20.2 ohms

i've checked all the resistors around the iSL, they are within specs.

 

[dukefawks]

Check 3V3 on PP3V3_S5_AVREF_SMC

 

[RedDemonic]

Check 3V3 on PP3V3_S5_AVREF_SMC

0.051v on PP3V3_S5_AVREF_SMC


i get 3.4v on pin1,3 on U5010


So U5010 is bad or one of the 4 capacitors on the bus is leaky and pulling it down?

 

[RedDemonic]

ok, the 4 caps are shorted to GND.

just compared with known working board.

 

[RedDemonic]

C5025 was the culprit. i took this one out and this cap does beeps on my fluke.

replaced with one from a donor board, now the board can power up normally.

tested all good.

thank you Duke and take care!

 

[dukefawks]

Just for reference, AVREF is the reference voltage for the A/D converters in the SMC. This is the reason all analog sensor were reading wrong.