A1932 820-01521 5V 0.2A.

[it-solve]

Seems like it has been cleaned by another company. Slight oxidation residue around U8200 and R3091.
Measurements around CD32s seems fine. No short anywhere.

T2 seems getting slightly warm.

Tried DFU both with keyboard comb and FORCE_DFU pads to 1.8 PP1V8_SLP2SR_PMUVDDGPIO which is nearby. i can measure 1.8V od SOC_FORCE_DFU, but no luck being detected under Apple Configurator

When connected to Apple configurator with SOC_FORCE_DFU jumper wire without battery or power supply, only on U3200 gets warm, while U3100 is not warming when connected to Apple Configurator via bottom USBc. Although no indication of any corrosions there, shall I replace U3100?

Where to start?

 

[2informaticos]

Check all adjacent traces and resistors of U2890.

All CD3215's LDOs present?

 

[it-solve]

Traces on the TBT ROM seems fine.


LDO's are present apart than PP1V1_UPC_XA/B_LDO_BMC - 0V - Not sure if this needs to be on at this stage.

 

[2informaticos]

1V1 LDO BMC must appear only on the powered port.

Did you check all resistors connected to U2890?
You've said to got one with oxidation.

 

[it-solve]

Sorry I must have not been clear. The one with oxidation was U8200. I have taken it out and cleaned underneath as it had bad solder joint on pin1


R3091 on U3200 looked like it had a corrosion marks. I was thinking it might have leaked under U3200 and was thinking to reball. But it is slight, compared to the ones with liquid I've seen before and CD32 still been ok.


"1V1 LDO BMC must appear only on the powered port." - is this on 20V turned on machine with CD32 engaged or when power is connected. Currently I dont get it on either of CD32's when 5V 0.23A


Everything seems fine around the TBT rom. No corrosion there, also MISO, WPL, SC seems to output at 3.3V range

 

[it-solve]

Also want confirm if this is the expected behaviour? Could this be a cause of the system not getting detected under Apple Configurator. Maybe faulty U3100 or its circuit

This is with SOC_FORCE_DFU jumper.
When connected to the top USBc U3200


When connecte dto the bottom USBc U3100

 

[2informaticos]

Seems to have problems on U3100 area.
1V1 LDO BMC is required for the communication between charger and the laptop.
If missing, the charger voltage can't be adjusted.

 

[it-solve]

Thanks. I have replaced U3100 with another one still stuck at 5V 0.23A on both ports.
Still missing 1V1_LDO_BMC . Only different now under IR is that both ports seems to heat up T2 evenly, unlike before.

Looking at the bootup sequence - https://logi.wiki/index.php/CD3215_Bootup_Sequence I went and replaced the U2890 thinking that might be a corrupted code. I got it from A1932 but older gen (2018) and still same.

Also not detected under DFU with or without the SOC_DFU_FORCE


Not sure if means anything but I get a DIM White LED near the battery connector on only on AC adapter, but not on battery.
LED seems to reflect to SYS_DETECT_LED

 

[2informaticos]

Check if U7800 delivers correctly SLPS2R and AWAKE voltages.

 

[it-solve]

Yes all SLPS2R are present from U7800
CPUAWAKE are at 0.75V
SRAMAWAKE is at 0.8V
1.2, 1.8, 3,3 and 0.7 VDDCPU awake as well are present

 

[2informaticos]

It should enter DFU then.

Did you test disconnecting auido flex?
Remove and inspect audio board for corrosion.

 

[it-solve]

yes tested with only bare board with SOC_DFU_FORCE pull up to 1.8V. Also in the case with disconnected audio and battery only.

There is no oxidation residue apart than U8200. But again it seems to be washed with something like aerosol can as feels oily.

 

[2informaticos]

Be sure to follow all steps to put the machine in DFU mode.

DFU Mode Restore (Macs) - LogiWiki

We have Apple MacBook and iPhone Diode readings and general fault finding information compiled by the leaders in this area

logi.wiki

Sometime is very difficult to get it.

 

[it-solve]

I can see it gets to it. When I connect the usbc meter to the top port and Apple conf to the bottom one, closer to the trackpad. The usbc meter reboots after 10sec with the keyboard shortcut to DFU.