no turn on 820-3209

[andrespi]

macbook air not turn on, fans do not turn on, not history avalaible

PP3V42_G3H_REG=3.42
PPBUS_G3H=8.48
PP5V_S3_REG=5.1V
PP3V3_S5_REG=3.3V
PPVCCSA_S0_REG_R=0.90V
PPCPUVCCIO_S0_REG_R=1.05V
PDDR_S3_REG=1.35V
PPVCORE_S0_AXG_REG=0V
PPVCORE_S0_CPU_PH1=0v
L7510=3.7 OHMS
ALL_SYS_PWRGD=0V

 

[2informaticos]

You need ALL_SYS_PWRGD, in order to enable CPU core voltage.
Remove Q7950 and check it again.

 

[andrespi]

ok. corrosion under Q7950 change Q7950, board turn on fan, but without video, no activitie usb, and PPVCORE_S0_CPU_PH1=0v, ALL_SYS_PWRGD=3.3vV
CPUIMVP_VR_ON=3.3v, P5V_S0_CPUIMVP_VDD=5V

 

[2informaticos]

Check R7402...

 

[andrespi]

R7402=91k

 

[2informaticos]

Check all SPI Bus Series Termination resistors and their traces.
Try known good BIOS.

 

[andrespi]

I already checked all resistors good, and programer bios, problem persists; some history; the board has all the test point color black

 

[2informaticos]

Possibly accumulated crap under BGA chips.
Reball SMC first.
Heat PCH and CPU with quality flux, if no change.