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Old 02-20-2017, 11:14 AM   #21
Bross
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Default Re: Shorted Graphic Card Gigabyte GV-N580UD-15I Rev 1.0 (nVidia GTX 580)

Thanks to both! Already asked to momaka, and the flux seems to be a RMA (for PCBs).

Hope I'll be able to pull out that rebel mosfet! The idea I have in mind by the moment is to wait the flux (it will take a little time, it comes from China and it was shipped three days ago ) and try again with it.

Cheers!
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Old 02-21-2017, 05:08 AM   #22
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Default Re: Shorted Graphic Card Gigabyte GV-N580UD-15I Rev 1.0 (nVidia GTX 580)

Well, send me a message when you have the flux on your hands, I'll be checking the post
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Old 02-21-2017, 12:10 PM   #23
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Cool Re: Shorted Graphic Card Gigabyte GV-N580UD-15I Rev 1.0 (nVidia GTX 580)

Great! Thanks, Drack, I'll let you know.
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Old 02-21-2017, 05:13 PM   #24
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Default Re: Shorted Graphic Card Gigabyte GV-N580UD-15I Rev 1.0 (nVidia GTX 580)

If you have a large tweezers, you can hold the mosfet and pull very carefully while yoy apply heat, this way you will know when the component is ready to be removed and you won't apply excessive heat to unwanted components.

And yes, i speak spanish too, chicharrero!.
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Old 03-05-2017, 07:13 PM   #25
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Default Re: Shorted Graphic Card Gigabyte GV-N580UD-15I Rev 1.0 (nVidia GTX 580)

Spanish thread ftw lol
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Old 03-07-2017, 12:50 PM   #26
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Default Re: Shorted Graphic Card Gigabyte GV-N580UD-15I Rev 1.0 (nVidia GTX 580)

Ey ey ey, ChaosLegionnaire is from Singapore, this thread is not that Spanish!

Charlie, allllmost, I live in El Hierro I just indicated my province.

Ok, so I'm back, because I decided to try again (without the flux, it hasn't arrived yet). This time I used gloves (for the tweezers), foil (covering everything but the mosfet to remove, like the first time) and heat sinks in its corners, and more time of heat gun expose. It hasn't move a thing! With 2000W... here is a photo:

removing mosfet - second try.jpg

Do you think this is normal? The plastic case has melted a little bit (with the tweezers) and nothing.

Did you have some PCB in your hands with components that you weren't able to desolder? In videos it seems easier than this -.- What you would do?
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Old 03-07-2017, 04:25 PM   #27
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Default Re: Shorted Graphic Card Gigabyte GV-N580UD-15I Rev 1.0 (nVidia GTX 580)

In this type of component, you also need to heat up the surroundings of the mosfet, keep in mind that the epoxy of the mosfet isn't a good thermal conductor.
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Old 03-08-2017, 05:40 PM   #28
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Default Re: Shorted Graphic Card Gigabyte GV-N580UD-15I Rev 1.0 (nVidia GTX 580)

Wait for the flux, is the best you can do for know
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Old 03-10-2017, 01:33 PM   #29
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Default Re: Shorted Graphic Card Gigabyte GV-N580UD-15I Rev 1.0 (nVidia GTX 580)

Once you get the flux if it still wont move you could try pre-heating the underside of the card to around 100c - if you don't have a dedicated PCB heater try some kind of radiating electric heat source or a second heat gun on low then once the card has reached 100c from heating the underside try your current method again on the already hot card.

Bear in mind it is a dual sided and probably multi-layer PCB (maybe the real question is how many layers of copper?) so it has quite some thermal mass (resistance to heating up only a small area) which can be why you are finding it difficult to get the existing solder to flow - also it is lead free solder which has a higher melting point than lead solder - if you can access all the solder connections from the edge of the device it can help to dilute out the existing "lead free" with "lead" solder for a lower melting point.

Some people (YouTube - use at your own risk!) would put it in an oven to heat it (be careful) thus reducing the thermal mass issue and then whip it out while hot and try immediately de-soldering - others trying to fix a dry joint would even cook it in an oven till all the solder melts and re-flows - then allow to cool slowly in the oven (be very careful) - have not tried either of those techniques - if you can call them that.

If you can access all the solder points / connections from just the edges you could try Chip Quick to lower the melting point of the current solder with a conventional soldering iron - as this is a forum about bad capacitors you have tried changing just the 8 Blue and Silver electrolytic (or are these polymer?) capacitors - haven't you?

In circuit testing of capacitors can sometimes work - for instance if you had an identical make and model of graphics card that was known to work perfectly then you could use a Capacitance and ESR tester to compare all the capacitors on both cards so you would then know if a certain capacitor cannot be measured in circuit because a capacitor is on the same circuit as another component that affects the reading or tricks the test instrument into giving an incorrect reading - so sometimes it is easier to just replace the capacitors to eliminate them - by the time you have removed them to test them you may as well just replace them.

Last edited by UHU; 03-10-2017 at 01:34 PM..
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Old 03-17-2017, 03:26 PM   #30
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Default That little rebel VRM MOSFET: desoldering oddisey

Thanks, UHU! About capacitors, I'm 90% sure that this mosfet is shorted, so first I want to know if I can remove it. And unfortunately I haven't a second heat source, and anyway I think it has a isolation layer in the middle, hasn't it? Could work that with this card?

IMG_0283.JPG

Anyway, I succeeded in an unexpected way. Finally, I got the flux. Tried with it, but nothing. My father was around in the place and told him about this. He thought it as possible to remove it just with heating pins with a soldier and pulling it out with a plain screwer. I tried that, but nothing. He offered himself to try that, but with more decision. You can guess the result:

IMG_0286.JPG

So... this is the mosfet inner, mh?

Had to say that, after that, I was disheartened with this. Flux arrived some days ago (and we did all of this then). This morning I went to the recycling point of my town to throw some old and broken computering stuff, and before that, I've been about to take this card there too, thinking that this went too far. But I didn't. Just an hour ago more or less, I talked with my father about new tries, and he proposed to cut the four pins and pull out the rest of the mosfet cover. We didn't found any copper traces on its side connecting them, so I agreed (I didn't feel actual danger). He succeed:

IMG_0287.JPG

In this way it seemed easier, so I tried again with the heat gun. Nothing. Ups, the flux! I put a little. So hard... so hard... but finally...!

IMG_0288.JPG

I think I can make a tutorial in Spanish called "desoldando un MOSFET por partes", haha!

So tomorrow I'll test the surround mosfets and order a 4935N from China as well (and more if I think it would be better). So, I have to wait a little bit more, but I'm not in a hurry I'll let you know when I have more news. Any suggestions, as always, appreciated (I'll check once this thread before ordering)
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Old 03-18-2017, 06:58 PM   #31
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Default Re: Shorted Graphic Card Gigabyte GV-N580UD-15I Rev 1.0 (nVidia GTX 580)

"Por partes" lol
I don't know why it's so hard to get those MOSFETs out, must be your heat gun. Mine is 1200w and there is no MOSFETs that can win against it
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Old 03-20-2017, 02:25 AM   #32
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Default Re: Shorted Graphic Card Gigabyte GV-N580UD-15I Rev 1.0 (nVidia GTX 580)

could be due to the amount of copper inside the pcb of this particular video card since this is a high-end video card. if the video card feels heavy even without the heatsink on, thats usually your clue...
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Old 05-14-2017, 07:52 PM   #33
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Thumbs up Re: Shorted Graphic Card Gigabyte GV-N580UD-15I Rev 1.0 (nVidia GTX 580)

Hi again! It's been a long time, I know... the mosfet arrived some weeks ago, but I was a little scared and was moving it forward in my agenda

I guess ChaosLegionnaire was right: there's so much copper, so the point is heating all the card first and after sold or unsold. This was the idea that got me scared...

But I did, solded that mosfet in its place, annnnnd...!



Like Doc said in Back to the Future III, it's funny that such a little thing can be that big problem (not sure about what he said exactly in the original version but I hope you know what I mean)

So, I learned, experienced and, besides, it's (at least apparently) fixed! Deluxe... Thank you everyone for your support! Badcaps rocks!

Now I have a second problem, that the computer rebooted after two minutes of watching a video in Youtube in 1080p with it but I think this is a power supply issue (theoretically with more power than needed, but got it from the trash as well and it's the only one I have at this moment capable for this card)... I have to do more tests. If I suspect it's because the graphic card, I'll post again here. If it's another thing and I need help as well, I'll open another thread.

Cheers!

Last edited by Bross; 05-14-2017 at 07:59 PM..
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