820-01700 - Stuck at 5V

[overshoot]

Hi,

I have that 16" 2019 board which won't turn on.
It's stuck at 5V 0.3A on any of the 4 ports.

I am the 2nd tech working on that board.

Visual signs:

board is clean, no liquid damage that I can see.
CD3217 have been reworked (reflowed or replaced) by the previous tech.

With battery, charger shows 20V at 0A.
Can't set the MacBook to DFU mode for some reasons.

Following the power sequence diagram from the 820-01598, I am stuck at PMU_PVDDMAIN_EN which I am not getting.

PP3V3_G3H_RTC_X 3.3V
PP3V3_UPC_XB_LDO 3.3V
PP1V5_UPC_XB_LDO 1.5V
PP1V8_SLPS2R 1.8V

U7800 LDOs:
LDO0 0.8V
LDO1 3V
LDO2 1.2V
LDO3 1.8V
LDO RTC 1.5V
VOUT_RTC 3.3V

 

[2informaticos]

Do you get all AWAKE and SLPS2R voltages?
Check the coils around U7800.
If yes, machine should enter DFU.
You can force it using SWK003 pads.

 

[overshoot]

I believe I do.
I've checked around U7600 and the only coils that don't have voltage are L7821 and L7822 which are for PPVCCPRIMCORE_PRIM_REG
I've tried again to get the machine to DFU and all I can see is the amperage going from 0.3A to 0.08A but machine does not get detected.
I've tried using the pads and same thing, amperage drops to the same value but nothing shows up on Apple configurator (I've tried 2 different machines in case)

Does that look like the board is going to DFU mode but there is communication problem, possibly with the USB-C port that is used to DFU?

 

[2informaticos]

Make only temporary contact on DFU_FORCE pads; release the contact after few seconds.

L7821/22 voltage should appear later; not needed for DFU.

Do not expect too much from a machine already messed up by someone else...

 

[No-Clean]

Did you fix this problem @overshot? I have one with the same exact issue