820-00928-A not turning on

iClub

Member
Good morning, I have a Mac that won't turn on, no oxidation.

I have taken the following measurements:


PPBUS_G3H: 12.65V
PP3V3_S0: 3.4V
ALL_SYS_PWRGD: 0V ~ 2.8V PULSE
PP3V3_S5: 3.3V
PLT_RST_L: 0V
 

2informaticos

Administrator
Staff member
If 3V3_S0 is stable, ALL_SYS_PWRGD should be stable too.
Post voltage for other S3 and S0 voltages, including CPU coils.
 

iClub

Member
PP1V2_S3 = 0v, pulsing 1.12V
PP1V2_S0SW = 0V, pulsing 1.003V
PP1V0_SUS = 1.005V
PP1V8_S3 = 0V, pulsing 1.73V
PP1V8_S0SW = 0V, pulsing 1.8V
PP3V3_SUS 3.32V

L7410 / 7420 - 0V
L7221 / 7211/7231 - 0V
L7330 - 0V, pulsing 0.8V
LA350 - 0V
LA300 - 0V
L7420 - 0V
 

2informaticos

Administrator
Staff member
Looks like no pulse at all at VCORE.
When you have doubts, an o-scope can help you; it catches the peak of any fast pulse.

Did you try SMC bypass mode?
 

iClub

Member
using o-scope:
L7410 40mV
L7420 40mV
L7211 40mV
L7221 40mV
L7231 40mV
L7330 1.08V
LA650 40mV
LA350 40mV
It does not go into SMC bypass mode.
 

iClub

Member
PVCCCORE_PH1_VCC oscila entre 0,354V ~ 4,661V.
Achei que fossem U7210 e U7420, então os substituí, mas nenhum resultado.

Testei sempre fora da mesa.

PP1V8_AWAKE_SW3C 0 ~ 0,881V
PMU_TO_SOC_AWAKE_PWRGD 0,170 ~ 0,827 V
PP3V0_AWAKE_LDO7 0V ~ 1,435V
 
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