RX 580 Repair

edavi

n00b
Joined
Feb 16, 2021
Messages
1
Hi all!

I've been into graphics card repair for about a month or so now as a hobby, and I've been picking up a lot of new things about electronics (that wasn't covered in my single EE class they put in our curriculum View attachment 1613536485975.webp).

I've bought about 10 dead cards ranging from old to new across Nvidia and AMD. So far 2 have been repaired, and I'm a little stuck on this next one. I've got a short from 12V to ground on the 6 pin connector. PCIE seems to be fine. The backstory to this card's previous owner was that a screw fell down the backplate between the PCB. Now I've dealt with a short from 12V to ground on my old GTX 970, and the source was a couple blown MOSFETs - not too bad of a repair, and felt proud of my probing skills.

The card in question is a RX 580 8GB Sapphire Nitro+. I'm learning as I go, but instead of separated mosfets like I'm used to, I believe it's using DrMOS(?) - hope I got that right. So the mosfets are embedded into this power phase? I see no visible damage on them or the card, other than two blown fuses I removed and temporarily replaced with wire. The DrMOS are SIC632. Now please correct me if I went about it wrong, but I checked each for a Vin to GND short internally and saw no issues (same resistance across the board). I've attached images of the card and marked in green with a marker what seemed to have no short (mosfets on the board).

Could I get some recommendations are where to look next in diagnosis?
 
Joined
Feb 16, 2021
Messages
4
My Sapphire Rx 580 8gb Pulse died back in May of 2020 with artifacts. I contacted Sapphire and asked them to help repair it but they didn't want anything to do with it. It's exactly why I will never give Sapphire my hard earned money ever again. I cannot recommend anything Sapphire and besides they only have a 2 year warranty. They might have a cool sounding name but they are not a good card manufacturer and the only reason their RMA is so low is because they refuse to RMA cards. The companies that are RMAing cards are honoring their warranty so it's never a good thing when a company has a low RMA. It's very deceptive and some people don't realize that. It doesn't mean their cards don't die. It just means they don't honor their warranty. Sapphire is a shameful company.
 
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Tygarbyte

n00b
Joined
Jun 15, 2021
Messages
1
Hi doing this as a hobby on/off also, have a look at the back of the card there is capacitor c31XX, use a smartphone with 10x zoom and see if you can see if there's any with hairline crack. I fixed a rx480 8gb nitro+8 , by replacing 2 fuse + 1 Cap.

I have a RX580 Pulse - Crystal heats up, PCB diagcard reads 00. Fuse seems fine, not sure what to check next.
 
Joined
Jul 29, 2021
Messages
59
You could try searching for the short by pouring some alcohol onto the pcb (or any other volutile, non-conductive liquid) and then get a lab-bench-power supply and limit the current to something like 1 amp or less. Now carefully put power onto the shorted rail and look out for the areas where the liquid evaporates rapidly. There should be the faulty component/s.

But do this on your own risk and dont blow out any more components or fry the pcb ;)
 

RazorWind

Supreme [H]ardness
Joined
Feb 11, 2001
Messages
4,105
You could try searching for the short by pouring some alcohol onto the pcb (or any other volutile, non-conductive liquid) and then get a lab-bench-power supply and limit the current to something like 1 amp or less. Now carefully put power onto the shorted rail and look out for the areas where the liquid evaporates rapidly. There should be the faulty component/s.

But do this on your own risk and dont blow out any more components or fry the pcb ;)
That often doesn't work on a graphics card. The whole board is designed as a heatsink, and the components that tend to fail are so large that you can't get them warm enough to make the alcohol evaporate visibly. Freeze spray works a little better, but even that is hard.

The truly proper way to do that test on a graphics card is with a thermal camera.

the OP: What is the exact resistance to ground you have on the affected 12V input? Also, have you figured out which VRM phases are actually powered off of that input? If it's the 6 pin, I'd guess the memory, memory controller, and maybe a couple of the core phases.
 
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