Lenovo X1 Yoga 6th Gen Nie uruachmia sie brak 20V

Witam
Pacjent jak w temacie. Zestawia się tylko na 5V, zlokalizowane zwarcie na L133 od strony VCC5_PD - 14 Ohm, przy próbie zwarciowej nagrzewa się znacząco U6319.
Na VCC3_LDO_PD - 51 Ohm
Domyślam się iż nie jest tu problemem U6319. Coś mi tu pachnie uszkodzonym CPU
Można tu jeszcze coś pomierzyć czy próbować rwać U6319?

Z góry dziękuje za pomoc.

Obsada:

MB: NM-D341
REV: 1.0
CPU: SRK03
KBC: MEC1503-EA2

mmike писал(а):Na VCC3_LDO_PD - 51 Ohm

Hello!
This voltage is generated by the LDO regulator inside the USB Type-C controller chip U192.
Remove the USB Type-C controller chip U192 from the board and remeasure the resistances to ground on the power rails "VCC5_PD" and "VCC3_LDO_PD".

mmike писал(а):Coś mi tu pachnie uszkodzonym CPU

I don't think the APU hybrid is damaged, at least not as this stage of diagnosis.

Thanks, bro!

You were right, after dismantling U192, the resistance on VCC5_PD and VCC3_LDO_PD increased significantly.
So I have two questions for you: since LDO generates U192, what is U6319 responsible for?
And secondly, is U192 programmable in this case? Will a 1:1 replacement do the trick?

mmike писал(а):what is U6319 responsible for?

This chip is an overvoltage and ESD protection device.

mmike писал(а): is U192 programmable in this case? Will a 1:1 replacement do the trick?

This chip does not require programming. You can use a brand new chip.

But since the LDO regulator inside the U192 was faulty, there may be an overvoltage on the power rail "VCC3_LDO_PD". So the chips U203, U6319 may also be damaged.

I understand that it is not possible to verify U203 and U6319 before replacing U192?

What's an actual resistance to ground on the power rail "VCC3_LDO_PD" with the chip U192 removed?

42 kOhm

This resistance seems fine, so the chips U203, U6319 probably survived, but I think there is no way to test them without soldering them to a working board.