820-01041-A not turning on

[iClub]

Good morning, this mac doesn't turn on, I imagine it's T2, but I can't leave it and DFU mode to restore.

Voltage;
PPBUS_G3H 12.31V; PP3V3_G3H_T 3.38V; P5VG3S_VSW 30mA.

 

[2informaticos]

Machine is not recognized in DFU?
Check if all SLPS2R and AWAKE voltages are present.

 

[iClub]

Do not.
The cable is new, I restored other machines with corrupted T2 using this cable.
Cable link I use: https://www.apple.com/shop/product/MWP32AM/A/thunderbolt-3-pro-cable-2-m

Voltages:
PP3V3_AWAKE 0V is oscillating.
PP1V2_AWAKE 200mV is oscillating.
PP1V8_AWAKE 60mV is oscillating.
PPVDDCPU_AWAKE 50mV is oscillating.
PPVDDCPUSRAM_AWAKE 70mV is oscillating.
PP0V8_SLPS2R 60mV is oscillating.
PP1V8_SLPS2R 74mV is oscillating.
PP1V25_SLPS2R_SMC_AVREF 145mV, is oscillating.
PP1V1_SLPS2R 107mV is oscillating.

 

[2informaticos]

You cannot put the machine in DFU mode, if these voltages are missing.
T2 is not even powered in such case.
Check diode mode on all these rails; compare with a good board.

 

[iClub]

Diode scale:
PP3V3_AWAKE 0.643
PP1V2_AWAKE 0.533
PP1V8_AWAKE 0.354
PPVDDCPU_AWAKE 0.024
PPVDDCPUSRAM_AWAKE 0.475
PP0V8_SLPS2R 0.186
PP1V8_SLPS2R 0.001
PP1V25_SLPS2R_SMC_AVREF 0.682
PP1V1_SLPS2R 0.272

By the measurements, this mesh is with low resistance PP1V8_SLPS2R.

 

[2informaticos]

"PP1V8_SLPS2R 0.001"
This is short for sure.

Lift L/R7813 and check where the short remains.

 

[iClub]

The short was in C7843, replaced, solved. Thanks!