Technical Support Dell Latitude 7390 Board LA-F29 Comes ON with battery but NOT with Charger.

[destinycenter]

Greetings. Thank you for all the trainings you've made available for us. I've really been learning a lot just these few months I started watching them.
This Dell in question comes on with battery when charged. The customer used to charge it on a similar machine before putting it into this one. I've confirmed this by using my power supply to supply battery voltage from the battery connector and it comes on.
But when I plug adapter voltage, nothing happens. Power Supply amps is 0.01/0.02. The main power rail is present. But strangely the 3.3v on the power button isn't present.
I also checked the Power management chipset which is intersil 9538h w736nu. I couldn't find the datasheet online, but got a previous model whose pins corresponded. The ACIN pin here which is the detection pin here is present but ACOK is not present. My suspect is the PWM chip.

 

[Ahmad Safari]

Hello
Be sure to test with another adapter.
In Dell laptops, the detect adapter is important.
Sometimes the adapter wire is cut in the detect path and the system has problems.
Sometimes on the motherboard, the path of the detect adapter is interrupted or the resistors in the path are damaged.

 

[destinycenter]

Thank you Sir for your reply & suggestion. It's a USB-C adapter not the common Dell adapter. Actually the adapter is detected on the detect pin of the chip. So It really does seem its the power management chip is the problem. Because all the right voltages are present on the chip.

Hello
Be sure to test with another adapter.
In Dell laptops, the detect adapter is important.
Sometimes the adapter wire is cut in the detect path and the system has problems.
Sometimes on the motherboard, the path of the detect adapter is interrupted or the resistors in the path are damaged.