Help ! Lenovo X280 doesn't start

[junkudo]

Hi guys

Lenovo X280 does not turn on.
Please help me someone.
The model of the motherboard is NM-B521.

The problem is as follows.

-"USBC_HV_GATE", which is the gate signal of the 20V MOSFET (Q263, Q264), is not output.

-The output source IC is U192: TPS65988, and 20V is applied to the IC chip.

-Replacing the tip does not improve it.

-I checked all power rails , but I couldn't find any short circuit.

Also, can anyone tell me what the abbreviation for HV is?

 

[Ferd]

Also, can anyone tell me what the abbreviation for HV is?

Most likely: high side mosfets.
How are you working on this board ? Any schematics or pictures to share . A

-Replacing the tip does not improve it.

The tip ? If you mean chip plz mention which chip isit .
History of the motherboard helps a lot .

 

[anfazi54]

maybe u can attach some picture from the motherboard for any suggestion