Dell Latitude 5530 not properly charging

[0x0null]

This Dell Latitude 5530 will not charge when turned off. when turned on and in bios it will charge properly and the adapter wattage is shown.

I noticed that when in bios if the charger is unplugged the bios still reports the laptop as charging and the charging light in front of the laptop stays on

When charging, PL4401 has a stable voltage of 12.8V however when plugged in but not charging the voltage alternates between 4v and 12v on PL4401

Please help

[mon2]

Have seen this fault before. Locate the charger IC and the Vcc pin. There will be a dual common cathode diode that feeds as the input, the battery voltage and also the adapter voltage. Only the higher of the 2 voltages should power the charger IC. In the past, this dual diode has been found to be defective. Suggest to flux and replace this part.

Do post your update with your status for future readers.

[0x0null]

Have seen this fault before. Locate the charger IC and the Vcc pin. There will be a dual common cathode diode that feeds as the input, the battery voltage and also the adapter voltage. Only the higher of the 2 voltages should power the charger IC. In the past, this dual diode has been found to be defective. Suggest to flux and replace this part.

Do post your update with your status for future readers.

Please could you point me to the diode?