Dell Precision 5520 / LA-E331P r2.0 starting into CPU-failure

[PeteH]

Hi everyone,

I have here a broken Dell Precision 5520 / LA-E331P r2.0 to play with
I found the schematics for r1.0, but not for r2.0.

The situation
- the laptop turns on, but the screen stays black -> the dell diag-LED shows the blink pattern for "CPU failure"
- the voltages close to the CPU stay at low
- I don't see any hotspots on the PCB (thermal imaging camera)
- some spots/areas on the PCB indicate some kind of liquid "damage"

Before I start digging though 70+ pages of schematics, maybe somebody has some good starting points on what to check.

Thanks in advance.
Pete

[PeteH]

I started going through the different voltages in the schematic for r1.0. All the voltages is marked with red are present.
The one that is not is +VCC_CORE. I can't see anything wrong with ISL95829 (the 29 is in the PCB not the below mentioned 25).
(I didn't measure the other voltages yet).

Not sure how likely this one is to fail. It show no damage and doesn't give off any significant heat.

Anyone any ideas?

[Muhurtam]

Hi man. I am a newbie at laptops repair, But if the ISL have the proper voltage input but no output............ it can be faulty. Not sure if you have a spare part to change it

[PeteH]

I'm wondering the same thing, but the setup with the ISL95829 and the different AOZ5029s makes it not as straight forward I think.

Has anyone knowledge / info how this setup works (or should work)?
Should the ISL95829 just start up VCORE if it has the correct input voltage?

[Muhurtam]

I cannot find the datasheet of ISL95829 looking for information about inputs to turn on the VCC-Core. If you can upload the image of the schematic, we can discuss together
Apologizes my english, i am Spanish