Question Part number of defective Mosfet on Gigabyte RTX 3090 Vision OC

[C0dR]

Hello,

I got my hands on a defective Gigabyte RTX 3090 Vision OC. I tested it on my mainboard beforehands and it seems to fried my mainboard (but thats another task...)
I was able to found the error, it was a defective/burnt MOSFTET and one small SMD capacitor was shorted and one resistor missing. After removing the MOSFET and capacitor, the GPU seems to work again.
Now I have two questions: Do I really need to replace the Mosfet+Capacitor? I know I am now missing one Phase on the GPU power rail but is it THAT bad? How much instability might occur or is it just going to perform worse?
Second and most important question: Does someone have the exact part number of the MOSFET and maybe capacitor and resistor values? It's the 3rd MOSFET from top on the right side (see image). I wasn't able to read it since the chip was quite burnt and I even had to dremel off some parts. Or maybe someone could provide some high resolution images of said area?

Thank you!

 

[1LiquidPC]

The part # and values are likely the same as the groups of similarly arranged surrounding components. This can common for SMDs in certain designs. I see it at work often, working with circuit boards. The writing on neighboring Mosfets should be the same part # as the other. It may be difficult the decode with the markings only, and not the full part #. What does the symbol look like on the other nearby mosfets to at least identify manufacturer. Digikey and other sites should sell these parts though higher $ for individual purchase vs. bulk orders. You aren't going to find the bill of materials and diagrams showing the values for for the cap, resistor, or Mosfet. Likely, you would have to remove the cap and resistor from another group, and get a reading for the value from a multimeter. All this said, how did you aquire the card, and what caused the damage in the first place? I'd be leary of using without a proper diagnosis and repair due to further risk of damage. I can't comment of the safety or reliability of running the GPU as-is with missing components.

 

[zx128k]

You should check for shorts first. Always check for shorts. If a VRM phase dies it could also send 12 volts to the gpu die and kill the chip.

Has close ups of the chips you are interested in.

Checking for shorts. 6:21 is the chips you are interested in. You can clearly see their markings.

 

[C0dR]

Thank you very much, that videos helped a lot. Yes I checked for short circuits. It seems that the GPU is running fine with one phase less, but I will further test it and try to undervolt it. Maybe thats enough to compensate for the missing phase, since soldering on this PCB is like horror, so much heat dissipation, I almost fried the caps. Anyways, I ordered the mosfet just in case.

 

[zx128k]

Not easy to solder those small components. Good job with finding and removing the faulty component. The gpu could work fine without a phase but I really have no idea about the risk.

 

[Gladiston]

My 3090 had a problem with the same Mosfet, the model is "BKU0 011T" apparently "AOZ5312UQI" I live in Brazil and I couldn't find it in my country, can you tell me if you had problems removing it and leaving it without?