Dell 7400 2-1 LA-G441P

[Markus1741]

Hello maybe someone can help me I have a Dell 7400 2-1 notebook with defective PD controller.
Motherboard probably had a short circuit due to a non-original USB-C power supply.
I bought both PD controllers from AliExpress and exchanged now it is so that unfortunately no fan runs and there is no 3 volt voltage on the pin 8 of the BIOS chip.
Thank you

[mon2]

The vbus voltage is 20v so that is a good sign that the pd controller is working. Test the other usb-c port as well for the same voltage.

Confirm the voltage to ground on each pin of the ldo at UT16.

Confirm the voltage to ground of the RTC battery.

[Markus1741]

The vbus voltage is 20v so that is a good sign that the pd controller is working. Test the other usb-c port as well for the same voltage.

Confirm the voltage to ground on each pin of the ldo at UT16.

Confirm the voltage to ground of the RTC battery.

Okay, thank you

Second USB-C Port also 19,5V

1 VCC = 19,69V
5 Out = 3,3V
3 NC = 0V
4 EN = 9,71V

JRTC1 = 0V

[mon2]

Is the RTC battery missing or is depleted? Replace this battery.

Confirm the voltage to ground of LDO_IN used by UT16. The USB-C power adapter voltage must appear here and from the same voltage, the ENABLE pin #4 should be a logic '1' to enable this LDO. Then 3v3 must be present on pin #5. If these conditions are met and the output of this LDO is absent -> remove all power -> meter in resistance mode -> measure the resistance to ground of pin #5. If this resistance is too low, then this LDO has turned off or is unable to handle the excessive loading on the downstream side. If the resistance is ok, then this LDO is possibly defective and must be replaced.