Some electronics / PCB expertise required on this second-hand GTX970.... Brown stain of some sort...

[SerKon]

Hi everyone, is there someone who could share his knowledge with me on the below please?

I recently purchased a 970 on marketplace and the card works fine with no stability or high temp issues. As you can see for the most part the card appears to be in good condition.

One thing I missed (because there was a backplate on the card) is this brown stain residue on the back. I can't tell if it's corrosion, flux residue or something else. It does not look like anything I was able to find online...

I have tried cleaning with 99.9 Isopropyl Alcohol and cotton swabs / microfiber cloth but none of it has gone away. This thing is rock solid...

I tried a plastic scraper very gently on a small line to see if I can scratch the surface and nothing, it will not go away....

The front side of the GPU has no visible issues whatsoever.

 

Any suggestions??

[ki8aras]

that you kind sir is called poop

[Mark Kaine]

water damage probably.  you're lucky it still works...

 

you could try pcb cleaner with a brush... but long term id be more concerned about the missing/ damaged smds.

 

basically as long as it works... cleaning alone isnt going to fix potential future issues however. 

[mariushm]

Use isopropyl alcohol  or even better acetone (nail polish remover is mainly acetone if you can't get pure acetone)  and use cotton ball swabs and gently rub that area to remove the crap. 

be gentle because those surface mounted resistors/capacitors may have weaker soldering joints due to that corrosion and you don't want to rip the off the board.

[Jurrunio]

Doesnt look like corrosion to me, more like milk tea stain or even toffee. Corrosion typically starts from soldering pads or the surface mounted components, not the black surface paint of the PCB. Yet in the pictures, it's brown even on the paint of the PCB.

[SerKon]

1 hour ago, Jurrunio said:

Doesnt look like corrosion to me, more like milk tea stain or even toffee. Corrosion typically starts from soldering pads or the surface mounted components, not the black surface paint of the PCB. Yet in the pictures, it's brown even on the paint of the PCB.

I know, that's what I'm thinking, it looks like a stain on top of the components, like a spillage of some sort.........

[SerKon]

1 hour ago, Mark Kaine said:

water damage probably.  you're lucky it still works...

 

you could try pcb cleaner with a brush... but long term id be more concerned about the missing/ damaged smds.

 

basically as long as it works... cleaning alone isnt going to fix potential future issues however. 

I don't disagree with you, what sort of PCB cleaner and brush type would you recommend?

[SerKon]

1 hour ago, ki8aras said:

that you kind sir is called poop

[Mark Kaine]

25 minutes ago, SerKon said:

I don't disagree with you, what sort of PCB cleaner and brush type would you recommend?

an  antistatic brush,  not specifically because its antistatic although thats another benefit obviously,  but because it should be made for exactly that purpose. 

and pcb cleaner... not sure what is available to you, i definitely prefer "kontakt" (German company) 

https://www.reichelt.com/de/en/contact-lr-400-ml-pcb-cleaner-kontakt-361-p26015.html?r=1

(comes with a small attachable brush, which is ideal)

 

You can also try acetone as @mariushmsuggested,  and tbh a soft toothbrush should also work.  im just not fond of the idea of using paper or cotton sticks etc as you have to be really careful not to rip those smds off.

 

its debatable if it wouldn't be better to do nothing... difficult decision imo.

[SerKon]

Ok guys, some positive developments... I was able to clean most of it off using pure acetone and a soft brush (thank you very much for the advice!). It... took... me.... a lifetime of scrubbing..... honestly I must have been at it for 40 minutes straight non-stop.

 

And even now the area around the spot, although it looks clean, it's somewhat glossy and sticky. Shall I keep cleaning until this goes away as well?? Problem is, I think I am only stirring the residue on the board now, not actually removing it (as in wiping it off)

 

On a positive note, all the electronics look intact to me; I guess we won't know until I plug it in and actually test it.

[Mark Kaine]

nice. nah i would actually leave it now, that residue looks kinda normal, dont overdo it imo... 

[SerKon]

1 hour ago, Mark Kaine said:

nice. nah i would actually leave it now, that residue looks kinda normal, dont overdo it imo... 

nice one mate, you are a life saver