Component identification on graphics card

RoboDisko · 06-08-2018, 03:18 PM

Hey. I've got a pair of 980ti graphics cards that I'm trying to get working. I bought the pair of them 'broken,' but one of them was working great. Then one day I noticed it wasn't working as well, but still working ok. Due to unbalanced power draw on the 2 pcie power connectors as well as early power throttling, I figured it was a VRM issue. Took it out to fix it up.

These cards have an 8 phase VRM. On the output there is a pair of components is parallel that look like diodes. On the non functional card, 2 of these components appeared burnt. On the functional card, 1 appeared burnt. I went on Mouser and ordered the only diodes that had "330" in the part number (3A 30V shockey).

Anyways, diodes came today. It was immediately apparent that they were the wrong package, and shortly after I was brilliant enough to realize that I was looking at capacitors. The reference designator wasn't a big enough giveaway the first time I suppose. Ugh.

Anways, 330, are we really looking at 33pF caps? That seems really small for... a 250W VRM. And can anyone point me in the correct direction of replacements? Or maybe I'm still missing something?

RoboDisko · 06-08-2018, 03:40 PM

And just before someone suggests removing and testing a component, I would like to add that I have attempted pulling 2 of the caps already. They use some crazy high-temp solder, and my "good" soldering iron isn't hot enough to melt it. (It's a metcal fixed temp.) My cheap-O adjustable soldering iron does get hot enough to melt it (It'd get hot enough to melt itself if you let it,) but by the time the component comes off, there is typically not enough of it left for an accurate test. If it comes to it, I'll pull one off and test, but hoping someone here can chime in before that.

**petehall347** · 06-08-2018, 04:30 PM

they are capacitors ..the c designation gives it away . you could initially test them for being shorted .
when removing try adding fresh solder or flux

RoboDisko · 06-08-2018, 05:34 PM

Ultimately, all of the capacitors are connected in parallel, as well as all the downstream logic. Line reads about 3 ohms on one and 4 ohms on the other. The non-working one that I'd expect to be shorted is the 4 ohm one.

I was adding leaded solder to the joint, but the quality iron wouldn't melt the joint to spread the lead, and by the time you melt the joint with the higher temp iron completely, I found it more effective to pull it off instead of trying to mix up a reasonable solder blend. This certainly isn't my first time soldering, but might be my first time surface mount lead free soldering.

**PeteS in CA** · 06-08-2018, 06:26 PM

I'm guessing 330uF tantalum caps.

RoboDisko · 06-08-2018, 09:20 PM

I'm guessing you're 100% right! I can find product offerings that meet those specs with the same physical package size as the ones I desoldered. Man, those suckers can be pricey! Mouser lists 330uF tantalum 7343 caps up to $30 each! Lucky, the ones I want are also the cheapest at $.73 each! (lowest ESR, one voltage range higher than I think I need) I'll get some ordered and let ya know how it goes.

By the way, anyone have a use for 16 b330a diodes?

06-08-2018, 03:40 PM	#2
RoboDisko New Member Join Date: Dec 2013 City & State: Idaho My Country: United States I'm a: Knowledge Seeker Posts: 15	Re: Component identification on graphics card And just before someone suggests removing and testing a component, I would like to add that I have attempted pulling 2 of the caps already. They use some crazy high-temp solder, and my "good" soldering iron isn't hot enough to melt it. (It's a metcal fixed temp.) My cheap-O adjustable soldering iron does get hot enough to melt it (It'd get hot enough to melt itself if you let it,) but by the time the component comes off, there is typically not enough of it left for an accurate test. If it comes to it, I'll pull one off and test, but hoping someone here can chime in before that.

06-08-2018, 04:30 PM	#3
petehall347 Badcaps Veteran Join Date: Jan 2015 City & State: worcester My Country: United Kingdom I'm a: Knowledge Seeker Posts: 2,680	Re: Component identification on graphics card they are capacitors ..the c designation gives it away . you could initially test them for being shorted . when removing try adding fresh solder or flux

06-08-2018, 05:34 PM	#4
RoboDisko New Member Join Date: Dec 2013 City & State: Idaho My Country: United States I'm a: Knowledge Seeker Posts: 15	Re: Component identification on graphics card Ultimately, all of the capacitors are connected in parallel, as well as all the downstream logic. Line reads about 3 ohms on one and 4 ohms on the other. The non-working one that I'd expect to be shorted is the 4 ohm one. I was adding leaded solder to the joint, but the quality iron wouldn't melt the joint to spread the lead, and by the time you melt the joint with the higher temp iron completely, I found it more effective to pull it off instead of trying to mix up a reasonable solder blend. This certainly isn't my first time soldering, but might be my first time surface mount lead free soldering.

06-08-2018, 06:26 PM	#5
PeteS in CA Badcaps Veteran Join Date: Aug 2005 City & State: San Jose, CA My Country: USA, Unsure of Planet Line Voltage: 120VAC, 60Hz & 115VAC, 400Hz I'm a: Professional Tech Posts: 3,086	Re: Component identification on graphics card I'm guessing 330uF tantalum caps. __________________ PeteS in CA Power Supplies should be boring: No loud noises, no bright flashes, and no bad smells. Where might is right There is no right. - Sophocles in "Antigone" ************************** All that is gold does not glitter, Not all those who wander are lost; - J.R.R. Tolkien, The Fellowship of the Ring ************************** To kill personal responsibility, initiative or success, punish it by taxing it. To encourage irresponsibility, improvidence, dependence and failure, reward it by subsidizing it.

06-08-2018, 09:20 PM	#6
RoboDisko New Member Join Date: Dec 2013 City & State: Idaho My Country: United States I'm a: Knowledge Seeker Posts: 15	Re: Component identification on graphics card I'm guessing you're 100% right! I can find product offerings that meet those specs with the same physical package size as the ones I desoldered. Man, those suckers can be pricey! Mouser lists 330uF tantalum 7343 caps up to $30 each! Lucky, the ones I want are also the cheapest at $.73 each! (lowest ESR, one voltage range higher than I think I need) I'll get some ordered and let ya know how it goes. By the way, anyone have a use for 16 b330a diodes?

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode