Advice on Recap Geforce 9800gt

[aidynphoenix]

got a 9800gt from a guy, he said it would give him the blue screen of death after some use. got the card installed it. it worked fine for about a week, even while maxing out the card in crysis2 and skyrim.
i figured his problems were heat issues because this card reaches 74c easily in my case, and my case has good airflow.
i did remove the heatsink and clean the card well, i removed and put new thermal paste on the card, and its about 4c lower on average now.
but its been working fine for about a week untill now, its making my computer lock up, not getting any blue screen's like he was. but my computer works fine with onboard and different graphics cards.

but because this card runs pretty hot, and because of its age, i Hope its just bad capacitors making the card unstable. i really dont know a whole lot about the purpose of these caps.

my card is the XFX 9800gt. it looks like this.
http://www.bit-tech.net/hardware/gra...ition-review/1

i have never recapped a graphics card before, i have recaped speakers and other audio equipment. a few powersupplies.
looks like it has all through hole type caps, 4 of which look like normal caps with the vinyl label around them, and the other 3 dont have the vinyl label. they are just aluminum with the info printed on the top of the
looks like values are.

black caps, with metalic bronze colored stripe indicating ground,
say "FJ 105c" has a [M] on the cap.
2x 1500uf 6.3v
2x 470uf 16v

aluminum caps,
x2 say
LF-1500-e-8x4

1x says
LF-330-c-892

i want to try and replace all those, i dont know what kind of caps i need, weather they are low esr, high ripple or whatever.
can you guys help me?

[mockingbird]

Re: Advice on Recap Geforce 9800gt

I see a combination of UCC Polymers and Panasonic FJ. These are both excellent capacitors and do not need replacing.

What I suggest you do is reflow the GPU. Don't do it in an oven because you have electrolytics there (And I don't think putting polymers in an oven at the temperatures required to reflow PB free solder is a good idea neither).

Use a heatgun. Read about doing this beforehand, there are several details you need to know like heating the entire board before to avoid temperature shock. Another thing you could learn before you do the reflow is technique. Using circular motions for instance while reflowing as opposed to holding the gun in one spot for too long.

If this doesn't help then there is nothing left to do as the 9800GT comes from a known defective generation of nVidia GPUs.

[aidynphoenix]

Re: Advice on Recap Geforce 9800gt

well heat gun seems dangerous to me. i have a heat gun, but how could you be sure you don't let the temp get too high?

oven seems easyier to manage the heat.
would it be a good idea to remove the caps, and then use the oven?

where can i learn about this, when i search for gpu repair/ gpu reflow, ect. i keep coming back to youtube and finding bad advice.
ty~

[Koda]

Re: Advice on Recap Geforce 9800gt

I've done reflows in my oven. I find them to be more reliable but you do need to remove the capacitors and after the reflow is done try not to move the card so you don't knock off any components while the card is hot. What you do is wrap the card in aluminum foil and cut out openings over the ram chips and the GPU. Make a few balls from aluminum foil and put them on a tray. Then place the card on top of the balls so it wouldn't sit directly on th tray. Chuck it in the oven, heat it in the oven at 250C/480F and let it cool for about 30min. Worked like a charm for me. Now I'm using a heat gun but reflows with a heat gun work for only 2-3 months and the oven trick seems to work a lot longer 8-10 months in my experience. Might be due to the heat spreading uniformly in an oven. Though it might be a capacitor issue after all, since the card was getting really hot even some of those quality capacitors might have gone bad due to heat (the electrolytic ones). Before you do this check the fan if it's working properly. If it spins slowly it's probably clogged with dust and it's what gives you headaches. Get a syringe and a needle, some machine oil with small viscosity and using the syringe oil it up, it should work fine. Hope any of my advice helps. BTW don't do a reflow in the oven you use to cook, lots of dangerous fumes from those PCB's and the solder.

[aidynphoenix]

Re: Advice on Recap Geforce 9800gt

After i first tested it and saw the temperatures, so i removed the heatsink and cleaned it in the sink.
than oiled the fan.
reapplied thermal paste.
i know its not overheating.

if i got a wooden clamp and had it squeeze the card, basically try and sandwich the heatsink down to the cpu, might that let me know if it is a bad solder connection under there?

also will 480f melt the plastic dvi connectors? or is that hot hot enough?

i think i want to replace the caps first. and if that doesent work il do the reflow.
reflow seems risky.

how long does the gpu need to sit at 250c?

and also, would weight on top of the gpu help to make a better solder connection?
might putting a few quarters stacked on top of the gpu add additional weight and help to get a better connection after it cools?

[Koda]

Re: Advice on Recap Geforce 9800gt

After i first tested it and saw the temperatures, so i removed the heatsink and cleaned it in the sink.
than oiled the fan.
reapplied thermal paste.
i know its not overheating.

if i got a wooden clamp and had it squeeze the card, basically try and sandwich the heatsink down to the cpu, might that let me know if it is a bad solder connection under there?

also will 480f melt the plastic dvi connectors? or is that hot hot enough?

i think i want to replace the caps first. and if that doesent work il do the reflow.
reflow seems risky.

how long does the gpu need to sit at 250c?

and also, would weight on top of the gpu help to make a better solder connection?
might putting a few quarters stacked on top of the gpu add additional weight and help to get a better connection after it cools?

The card should be put in non-preheated oven with the dial set at 250C once you get the card in. No extra weight needed on top of the GPU (it actually may create more problems i.e. solder bridges and trust me you don't want that). As long as you wrap the DVI connectors well with aluminum foil it should be fine. Just don't expose any other components of the card directly to the heat and you will be fine. Squeezing the gpu won't help if the problem is with the memory BGA, but you might as well try it. Just don't apply too much pressure cause you might break the die of the GPU.

[aidynphoenix]

Re: Advice on Recap Geforce 9800gt

any chance of components on the bottom of the pcb falling off?

so i put it in a cool oven, than let it preheat to 250c, than once it reaches 250c, i turn it off, open the door and let it cool before moving or touching it. remove the foil, put the caps back on it, than give it a try?

[Koda]

Re: Advice on Recap Geforce 9800gt

any chance of components on the bottom of the pcb falling off?

so i put it in a cool oven, than let it preheat to 250c, than once it reaches 250c, i turn it off, open the door and let it cool before moving or touching it. remove the foil, put the caps back on it, than give it a try?

No chance if you wrap the card well with aluminum foil and sit it on top of solder balls, that way not much heat reaches the bottom of the card. Also you need to put it in a cool oven then turn the dial to 250C/480F and let it sit there for about 8-9 min. Afterwards let it cool, put caps and heatsink on and try it out. That's pretty much all you need to do.

[mariushm]

Re: Advice on Recap Geforce 9800gt

I have an issue with the 250c value...

The solder used turns liquid at about 235c-240c but some of the heat gets dissipated in the copper layers. You can't just preheat the oven at 250c and put the card in cold, as you'll damage the board.

Preheat the oven to about 100-120c, put the card in, gradually increase the temperature in the oven to 250c within about 3-4 minutes to let the card layers expand without cracking, then once you're at about 250c keep it there for about 20-30s. So the card will have to stay at about 20-30s at 250c then you turn off the heat and crack open the oven door, so that the heat will gradually go down. This time where the card goes from around 250 down to about 200 as you leave the oven door cracked open gets added to the 20-30s of staying at 250c.
After about a minute or two , open the door completely until the card is cold enough to touch it.

Here's a pdf showing the heat curve for a lead free solder paste, which is the kind that's typically used in RoHS soldering:

https://cdn.badcaps-static.com/pdfs/...f3690422b9.pdf

[Koda]

Re: Advice on Recap Geforce 9800gt

If you read more carefully I said to put the card in a cold oven, then turn the dial to 250C, that way the temperature of both the card and the oven increases gradually so the preheating and reflow steps are done simultaneously.

[aidynphoenix]

Re: Advice on Recap Geforce 9800gt

ok can you explain solder balls to me please?
at first i interprated what you said as making 4 balls of foil to let the card rest upon to keep the bottom of the card up off of the metal oven rack.. am i supposed to make a bunch of balls ?

[Koda]

Re: Advice on Recap Geforce 9800gt

Solder balls are what holds the chip soldered to the card.
http://www.caltexsci.com/bga_scope.htm
http://en.wikipedia.org/wiki/File:BG...e_sideview.PNG

Aluminum balls are what you put the card on while you are reflowing it. The aluminum balls should be about 3-4cm in height.

[Koda]

Re: Advice on Recap Geforce 9800gt

Hey aidynphoenix, how did you do with the reflow, I'd love to hear an update about the card.

[aidynphoenix]

Re: Advice on Recap Geforce 9800gt

well i couldent heat the solder up hot enough with my iron to remove the caps, so i ordered exact replacements, and bought a new iron, i put it in the oven without removing them. im now just waiting on the 1500uf caps to arrive so i can recap it and give the card a try.
by mistake i ordered the 470uf caps twice, and am waiting on the 1500uf caps to arrive.

[Koda]

Re: Advice on Recap Geforce 9800gt

Do the caps look damaged from the heat?? If they are not bloated you can still try out the card. I have done this before I knew that I should remove lytics before baking Next time before you try to unsolder caps add some flux to the pads thin your iron tip and add a little solder to the leads. And make sure you use 40-60w soldering iron.

[aidynphoenix]

Re: Advice on Recap Geforce 9800gt

yea the caps were buldging. i had a cheap radioshack iron, wouldent heat the solder up enough. i got a weller 8200n now that seems to work well. i got the 470uf caps replaced, but still waiting on the 1500uf caps to arrive.

[aidynphoenix]

Re: Advice on Recap Geforce 9800gt

ok well its recapped now.. its working.. but i got a few graphical problems in one of the tests in 3dmark 03.
the troll's arm was transparent, and the girl with the sword was flickering.. however all the other tests were fine.. sofar no crashing yet though. scored 30,623. which seems right. i think il find some more difficult tests to try.
il also try a different driver, this one is the driver that came with windows update.

[aidynphoenix]

Re: Advice on Recap Geforce 9800gt

well sofar so good. no other glitches/artifacts.
tried, fear3, crysis, farcry2, got a few hours of playtime, no issues yet. guess i'm going to take it out of my backup machine and into my main rig so i can keep a eye on it.

been saving up for kepler for awhile, im excited

[Koda]

Re: Advice on Recap Geforce 9800gt

I'm glad to hear that, now you got a working 9800GT congratz!! Just to be safe run furmark on it for a few hours.

[aidynphoenix]

Re: Advice on Recap Geforce 9800gt

now that i think about it, there was a number of graphics cards i had in the past that would show artifacts or crash... i probably could of had fixed those too like this....

thanks for showing me this awesome skill guys.