Question Dead EVGA 1080 GTX FTW - Stabbing questions

[Tjudawous]

Hello all,

Long story short, PC wouldn't boot up. Did some standard tricks to troubleshoot down to bad graphics card. The bad card in question is a EVGA 1080 GTX FTW.

I'd like to fix the card, so I'm trying my hand at stabbing. There are some great stabbing guides for testing resistances. I don't have a power supply and don't want to plug it back into my only PC tower at this time so I'm kinda stuck with just testing with continuity and resistance.

I've checked the 3V, 12V rails on the card's pins that plug into the mobo, seem okay. I'm seeing some inconsistencies in some of the continuity and resistance checks across the MOSFETs, which makes me think it could be those. Without a schematic I'm not sure though. Further, I've tried to look up the datasheet for the 81382 20FA MOSFETs to no avail, there are similar ones but with different pinouts. The closest one I found didn't appear to provide a datasheet.

For reference, these are the measurements I'm seeing across the MOSFETs:

The bottom 5 show only about a 1 Ohm resistance and 0V continuity check, but the upper 5 + 2 MOSFETs show about 1.3 kOhms and 1.7V. The inductors to the left seem pretty consistent in their measurements. Anything else I should be looking for? The pins on the MOSFETs are really tiny and there's that (what I assume to be) non conductive oil or thermal compound or something smeared across parts of the board.

Any help here is appreciated, I couldn't find a specific 1080 GTX FTW stabbing guide nor could I find charts with any or all expected measurements across components. Might be one buried somewhere on the internet that the google has yet to bear fruit on. I decided I'd reach out here since I really want to repair this card, just not a lot of data to go with, any pointers or data points are appreciated!

 

[4745454b]

Let's assume you found the issue and it is those mosfets. Do you have the skill and equipment to solder in New ones on a multi layer pcb? Unfortunately parts die. Unless irs under warranty I'd just replace.

 

[Tjudawous]

Do you have the skill and equipment to solder in New ones on a multi layer pcb?

I don't have a stencil but otherwise I have what I need (paste, syringe, hot air rework, etc.). So, yes

Do you know any forums that might have this level of expertise they are willing to share in terms of what readings to expect, if not here? Not having data sheets on the mosfets makes me less certain

 

[4745454b]

You'd probably need to measure from a working card.

Where do the working new parts come from? I don't think those mosfets are bad. The fact that they are all showing one value then changes to a different value to me just says they are powering different things. They can be commonly found in a 6+2 config.

 

[Tjudawous]

I don't think those mosfets are bad. The fact that they are all showing one value then changes to a different value to me just says they are powering different things.

This is kind of what I was thinking but wasn't sure, no benchmark card to measure so I was hoping to find something that had those measurements buried on the net somewhere, but I'll keep digging.

Wanted to validate test results before trying to heat the gpu