NM-B471 Lenovo T480s don´t charging

[master3112]

Hi guys
I need help with a Lenovo T480s NM-B471.
The device works via power supply and also via battery. However, the battery is not charging. If I start the device via battery, the power supply is deactivated and the battery is empty at some point.
I have measured and found the following. When the mains adapter is connected, is VSYS= 20V, but this should be 15V. At the PQ102, which is responsible for this, I have 20V at the gate (pin 1). However, 15V should be there. Because the voltage is too high, PQ103, which should charge the battery, remains closed. I have already replaced the PowerController (PU101), same behavior. When the device is running on battery power, VSYS= 11.8V, i.e. the battery voltage. Does anyone have any ideas? THX

[mon2]

Both PQ101 and PQ102 are suspects. Remove all power. Meter in resistance mode.

Measure resistance of:

source & drain
source & gate
gate & drain

of each dual mosfet. Post each measurement. Each must be hundreds of k ohms or more if ok.

[Sephir0th]

Note that these are Dual-Mosfets. But it indeed strongly sounds like PQ101 being internal shorted when getting 20V at VSYS