820-01598 No Boot

[ClerkenwellMacs]

PP3V3_S5 - 0v
PP1V8_S5 - 0v

SSD0_VR_P2V5_PGOOD - 2.27v
SSD0_PMIC_RESET_L - 1.79v
PMU_ONOFF_L - 3.25v

 

[2informaticos]

Check if all SLPS2R and AWAKE voltages are present.
Try revive option (not restore) in DFU mode.
If you are not sure about which macOS version is installed, try the second machine with Catalina, as Big Sur too.

 

[ClerkenwellMacs]

To confirm that's,

PP0v8_SLPS2R
PP1v1_SLPS2R
PP1v8_SLPS2R

PP0v8_AWAKE
PP1v1_AWAKE
PP1v8_AWAKE

???

I have tried Revive, there was no error this time.

The machine no longer shows recovery in Configurator, it just says apple controller under the box which appears.

I can still get it into DFU

Does it make a difference if I am using configurator on a Big Sur or Catalina device? Have been using Catalina. No idea which OS the 820-01598 had installed.

 

[2informaticos]

If all present, try DFU again, as above specified...

 

[ClerkenwellMacs]

PP0v8_SLPS2R - 0.79v
PP1v1_SLPS2R - 1.19v
PP1v8_SLPS2R - 1.79v

PP1v8_AWAKE - 1.79v
PP3v3_AWAKE - 3.27v

 

[ClerkenwellMacs]

I tried it on a laptop running Catalina, images show the sequence.

The laptop remains unresponsive post Revive.

Will try on Big Sur

 

[ClerkenwellMacs]

Ok, exactly the same result when reviving using an A1708 Macbook running Big Sur.

 

[ClerkenwellMacs]

So feels like that's completing as not coming up with an error.

Should the processor come on and how best to check?

 

[2informaticos]

Start macOS installation from Apple Configurator, if data is not important in T2 machine.

 

[ClerkenwellMacs]

Can that be done from Configurator?

How is it done?

Also I've yet to see anything on the screen of this MacBook. Would have thought after a revive I would get the Battery icon etc

Thanks!

 

[ClerkenwellMacs]

I have completed a restore, no error message. When configurator completes the fan spins for 1 second before going off again.

Nothing shows on screen.

 

[2informaticos]

Do you get voltage on big coils now?

 

[ClerkenwellMacs]

PP5V_G3H - 5.09v
PP3V3_G3H - 3.29v
PPVIN_S0SW_LCDBKLT - 0v
CHGR_LX2 - 12.92v
PPVCCEDRAM_S0_REG_R - 0v
PPVCCGT_CPU_PH1 - 0v
CPUGT_SW1 0v
CPUGT_SW2 - 0v
CPUCORE_SW1 - 0v
CPUCORE_SW2 - 0v
PPVCCSA_CPU_R - 0.1v
PP0V95_S0_CPUVCCIO_REG_R - 0.95v
PP1V2_S3_REG_R - 1.24v

Where voltage is present it is on both sides of the coil.

 

[ClerkenwellMacs]

I am now getting these, before they were 0v

PP3V3_S5 - 3.3v
PP1V8_S5 - 1.8v

 

[2informaticos]

VCCGT refers to iGPU, not required on boot.
But CPU must get CORE voltage always.
VCCSA should appear first; check diode mode there.

 

[ClerkenwellMacs]

PPVCCSA_CPU_R - GND = 090 in diode mode (Positive on ground)

Is this a little high for a straight up short?

Thanks

 

[ClerkenwellMacs]

So the short is coming after U7210

Im getting all voltage in

PPBUS_HS_CPU - 5v
PP5V_G3S_CPUREG_MISC - 5v

CPUCORE_FCCM - 2.5v
CPUCORE_PWM1 - 2.5v

Nothing on PPVCC_CPU_PH1.

Is it worth removing U7210 to see if the short goes or do you think the issue is further downstream or the processor.

The processor is warm but not hot.

 

[2informaticos]

Whic is the exact ohm value of that "short"?
CPU core power rail can have very low values as normal.

 

[ClerkenwellMacs]

CPUCORE_SW1 - GND I am getting 2.0 ohms

Getting my head round lots of this. I am using 200 as the measuring option on the Multimeter.