MSI x370 Gaming pro m/b repair - in progress

[Nexxen]

Hello,

I have this m/b,
- without a cpu it powers on; red LED on the cpu (meaning no cpu detected error)
- with a cpu it doesn't power on.

This is a normal behaviour for MSI boards when they cannot read the BIOS chip.

The BIOS chip doesn't get its Vcc because of another failed component, one you helped me identify, CCH (MP5077GG). This outputs the Vcc for the BIOS.
Another YTuber -Tech Cemetary, B450 - had this issue (), no Vcc = no power on.
I wanted to read the BIOS chip but until I removed the CCH, I simply couldn't because of Vcc shorting to ground - this indicates that there is a short on Vcc 100%.
After that I could read/write/test no problem.

3 other components were dead and desoldered, ASM1408 (multiplexers).


I have a few questions:

- cpu mosfets (high) get the +12V, but the (low) mosfets don't output anything, is this a normal behaviour due to no cpu installed? (Nikos PK616BA + PK632BA groups (5 of these groups).
- the fact that the MSI Eazy Led works, is a good indicator of something or just a mechanical response, and everything else could be dead?

- without a multiplexer, is just the PCIe and M2 ports not working (thos connecting to the SB)? and everything else connected to the cpu lanes will?



It's long but I'm a noob and can't 100% clear out all my doubts.

Any help is welcome!!

[Nexxen]

I already ordered the new components, waiting to resolder and test.

[Nexxen]

After getting help on how to resolder the CCH I could test the board.

It didn't blow again, which is already something.
The required voltage of 1.8V isn't being generated preventing the board from powering on (BIOS fails to init).

I located another component that isn't outputting the 1.8V I suspect is required to trigger the CCH (like a Gate but I'm not sure).

I'll order that one QFN 12, MP2147GD-Z https://www.monolithicpower.com/en/documentview/productdocument/index/version/2/document_type/Datasheet/lang/en/sku/MP2147GD-Z/document_id/835/

I've learnt many things up to now, I take this as win-win even I fail to revive this board.


Next post will be after resoldering the QFN.

[Nexxen]

This other smd gets terribly hot, impossible to stick my finger on it.

It should output 1.8V but only 0.45V come out.
I guess that it's either broken or another component is dead and shorting to Ground.

I also have a GS7133 to check. As I'm learning things I do understand more and more but still too far from knowledge.