Broke A Capacitor Off Graphics Card, Need Advice Please.

smarty · Joined: 09 Jul 2006 Posts: 5

I was trying to remove my Nvidia 7800GT computer graphics card today and accidentally broke a capacitor off the board. I took the card out and had a look then I refitted the card, everything appears to be working fine and I have ran several stress tests like 3D mark etc and it is performing as it should, it is also working fine in games. The capacitor that came off was a surface mount 100UF electrolytic capacitor, I really do not know how to re-solder this as there is no room to work with whatsover. However if you look at the pictures in the links (second one) it looks like the board was designed to take either a surface mount or a through-hole radial mount capacitor. I was thinking of buying a 100UF radial mount electrolytic capacitor to fit to the board, the only problem is that I do not have a clue what voltage the capacitor is. Does anybody have any idea please? The card is pretty expensive, as if it was a cheap one I would probably not be as bothered.
http://img.photobucket.com/albums/v495/wokeye/PICT40145.jpg
http://img.photobucket.com/albums/v495/wokeye/PICT4016.jpg
http://img.photobucket.com/albums/v495/wokeye/PICT4022.jpg

Guest · Posted: Sun Jul 09, 2006 6:34 pm Post subject:

The links to the pictures say that the image is no longer there. I guess it may be supplied by the 12 volt rail, in which case a 16 volt capacitor may be O.K. What voltage do you measure?

smarty · Joined: 09 Jul 2006 Posts: 5

Sorry I have updated the links they are working now. I have not measured the voltage as I have not got a voltmeter, although I could borrow one from work. Probably the best way. Take a look at the pics anyway, they work now Embarassed

Guest · Posted: Mon Jul 10, 2006 1:29 am Post subject:

dEAR sMARTY

The part is either "decoupling" the voltage line or just smoothing the 12volt rail or 5 volt.So what i'm trying to say is that you do not need to replaced that
cap. Laughing

vtech · Joined: 08 May 2006 Posts: 1264 Location: USA

smarty · Joined: 09 Jul 2006 Posts: 5

Yes the legs are still intact on the bottom of the capacitor, but there is next to no room to get a soldering iron in as the legs are very short and bent at right angles to the capacitors base. I am not to clued up this, is some special type of soldering iron needed to re-solder such parts when the space to work in is next to nothing. That is why I mentioned a radial mount capacitor instead. But as stated I am no expert Rolling Eyes

vtech · Joined: 08 May 2006 Posts: 1264 Location: USA

There is no problem using radial mount. As far as the short legs, you need to have a small tip soldering iron & the way to do it is to apply a bit of solder flux on the traces & simply lay the cap back on the trace . You can reflow the solder by carefully touching the pad right up to the tiny leg of the capacitor. (Part of my daily job).

smarty · Joined: 09 Jul 2006 Posts: 5

Thanks for all the help there is no way that I can re-solder the surface mount capacitor as there is not enough room. I have measured the voltage and it is 12V. Yet this is DC the reading was just rubbish on AC, I do not know how a computer works. So I am looking for a 12V through board capacitor then?

smarty · Joined: 09 Jul 2006 Posts: 5

A 12V 100UF radial mount capacitor I meant. Or can you not get a 12V should I get a 16V.

Guest

If normally 12v at this location then you would fit a 100uf 16v 105deg radial subminiture electrolytic capacitor observing the polarity.
The next size up would be 25v and would work just as well be physically may be a bit large.