Lenovo x1 carbon gen 9 - strange power problem.

[pevata9811]

Hello, i have Lenovo x1 carbon gen 9. Laptop doesnt start on battery, but if you plug in the adapter and start the laptop, then unplug the adapter laptop will work fine on the battery. On adapter, laptop also charges. Do you have any ideas?

[FriedFred]

The PD (power delivery) IC seems to me is damaged. The PD Controller is the managing IC between the mains power supply, the battery, the PD USB-Type C port, and the Mainboard.

[pevata9811]

The PD (power delivery) IC seems to me is damaged. The PD Controller is the managing IC between the mains power supply, the battery, the PD USB-Type C port, and the Mainboard.

Thats the schematic. Which IC you think is suposed to do this ?

Link to schematic --> https://www.badcaps.net/forum/troubl...d341-schematic

[FriedFred]

Have you ever tried another battery? How is the sytem behave after fully charged the battery? Same behaviour?
It can also be the initial battery circuit, like the fuse "F9", and diode "D19".
Also check the MOSFET "Q34" for proper function.
All current flows through this MOSFET. So, if it's damaged and the so-called "body-diode" is there only, then the battery can take current, but it can't deliver.

[pevata9811]

Have you ever tried another battery? How is the sytem behave after fully charged the battery? Same behaviour?
It can also be the initial battery circuit, like the fuse "F9", and diode "D19".
Also check the MOSFET "Q34" for proper function.
All current flows through this MOSFET. So, if it's damaged and the so-called "body-diode" is there only, then the battery can take current, but it can't deliver.

i dont have another battery but laptops can work only on battery so i consider it godd. F9 , D19 , Q34 all good. Also all mosfets around battery cirquit.

[FriedFred]

Is there a standby voltage, 3.3V and/or 5V, anywhere on the board, if external power supply is not connected and battery is connected?

[FriedFred]

The broken component can be a double-diode in SOT23. One side is connected to the power connector, the other diode is connected to the battery. Both lines feed the standby-voltages which the EC-chip needs to monitor the ON/OFF-Switch and start.