A2251 820-01949

[ipetro]

flooding near USB-C ports J3300_CXT, cleaned!
consumption 20v /0.000 stable! no in DFU.
replaced battery with charged one! PPBUS_G3H=12.4v. need your help

 

[ipetro]

PP5V_G3S=5v
PP3V3_G3H=3.3v

 

[2informaticos]

Check all SLPS2R and AWAKE voltages near U7800.

All ports have the same behavior?

 

[ipetro]

outside the case the board consumes (without battery) 20v/0.084 but still not in the DFU

 

[ipetro]

PP1V8_SLPS2R=1,8v
PP1V8_SLPS2R_SOC_LPADC_RC=1.8v
PP0V8_SLPS2R=0.8v
PP1V8_SLPS2R_SOC_LPOSC_RC=1.8v
PP1V25_SLPS2R_SMC_AVREF=1.249v
PP1V1_SLPS2R=1.1v
P1V1SLPS2R_SW1=1.1v
P1V1SLPS2R_SW0=1.1v
P1V1SLPS2R_FB=1.1v
P1V8SLPS2R_SW0=1.8v
P1V8SLPS2R_FB=1.8v
PP1V8_SLPS2R_PMUVDDGPIO=1.8v

PPVDDCPUSRAM_AWAKE=0,800v
PPVDDCPU_AWAKE=0.755v
PP1V8_AWAKE_SOC_TSADC_RC=1.8v
PP1V8_AWAKE=1.08v
PP1V2_AWAKE_SOC_PLLSOC_F=1.2v
PP1V8_AWAKE_SOC_FMON_RC=1.8v
PP1V2_AWAKE_SOC_PCIEREFBUF_F=1.2v
PP1V2_AWAKE_SOC_PCIEPLL_F=1.2v
PP3V3_AWAKE=3.3v
PP1V2_AWAKE_SOC_PLLCPU_F=1.2v
PP1V2_AWAKE=1.2v
PVDDCPUAWAKE_SW0/1/2/3=0.755v
PVDDCPUAWAKE_FB=0.755v
PVDDCPUSRAMAWAKE_SW0=0.800v
PVDDCPUSRAMAWAKE_FB=0.800v
PVDDCPUAWAKE_FB_R=0.755v

all indicators look perfect! I can't forcefully transfer to DFU either! Maybe there is a problem with the SSD?

 

[2informaticos]

Bad SSD can impede to complete DFU.
However, machine should enter DFU.
We many times seen machines solving missing SSD voltages after DFU restore.
So, working SSD is not required to enter into DFU.

Did you try external switch method to force DFU?

 

[ipetro]

Did you try external switch method to force DFU? -yes ! not working.

I examined the SSD area and found that the PP0V9_SSD0 line = 0V. and in diode mode 0.030. in resistance mode 30 megaohms. I removed the SSD but the readings did not change.

 

[2informaticos]

You can't get 0.030 in diode mode and 30 Mohm in the same point!

 

[ipetro]

If the SSD reads P13, does that mean the SSD is good?

 

[2informaticos]

If P13 can read NANDs, SSD should be good.
However, as I told you, machine should enter into DFU even with SSD problems.

Disconnect touch ID and try to force machine into DFU using 2 switches; for ONOFF and DFU pads.

 

[ipetro]

PMU_ONOFF_L+gnd= power button
SOC_FORCE_DFU+PP1V8_SLPS2R=button DFU
this is the correct connection ?

 

[2informaticos]

Yes...

 

[ipetro]

I tried everything! It doesn't work! Since I have all the power and it should work, I'm inclined to think that maybe the MacBook is in DFU but there is no signal on the USB for another Mac to recognize it! Maybe there is a problem with the Thunderbolt or something like that! I even installed another SoC and it also didn't go into DFU but it should!

 

[2informaticos]

If problem persists after changed T2, you may have problems with the USB-C port dedicated to DFU.
Check around U3100_X and J3300_CXT.
Something is affected by corrosion there.
May need to reball/change CD3217 chip...