Dell Inpiron 3521 (LA-9104P)

[WhiteWolfHellas]

Hello, I have a Dell with motherboard VAWOO LA-9104P REV 1.0

I tried to upload a video with the symptom here but it fails to upload, so I will describe what it does.
Pressing the power button makes the fan spin for a second and then stop. The power leds also lights up for a second before it turns off.

I have 19.5V, 3.3V and 5V present, but my spi chip UH6 has 0V.
Following the schematic, I see that PU200 has 19.5Vin as well as output voltages.

Can it be a bad bios chip then?

I have checked the +3VLP and it is present.
What else should I check?

[mon2]

Re: Dell Inpiron 3521 (LA-9104P)

It is a Dell so the power adapter is critical to booting the logic board. Each Dell power adapter features a single wire (Dallas / Maxim semiconductor) interface to identify the specs of the adapter. This communication must occur else the adapter is assumed to be too weak to power the laptop.

Check the voltage to ground of ADAPTER ID. This will be a signal on the power connector. It must reach the EC and often the mosfet in series between the connector and the EC gets damaged. This will halt this ID communication.

Search the forum for this topic. There are many similar cases of the same.

Be sure the adapter is from Dell and of the correct ratings.