eVGA 7600GT Cap Replacement Question

[buriedpast]

Hi all, this is my first post here and first thought on recapping. Old hat with soldering, so I figure this will be a nice project.

My 7600GT has the infamous Sacon FZ caps that I'm going to replace - it died yesterday and I couldn't figure out what happened until finding this site and remembering the couple of "pops" I heard ... rung a bell.

I''ll replace all 3 types: 470 uF 16V, 1000 uF 16V and 1500 uF 6.3V. From what I've determined on the forums, the FZ ripple/ESR specs are 1,800 and 0.022.

The replacement Rubycon I figure to buy here will be: MCZ for the 1500 and 1000 caps and MBZ for the 470 caps.

I've read many recommendations for the MCZ and MBZ caps as replacements for Sacons and also have read that I should replace with "more ripple and less ESR". The MCZ caps meet that spec, but it appears the 470 MBZ will be exactly opposite with a ripple = 1140 and ESR = 36 (which I assume is actually 0.036)

Will using the 470 MBZ present a problem? And if so, any recommended cap for a replacement?

Thanks in advance.

[PCBONEZ]

Re: eVGA 7600GT Cap Replacement Question

That help a little?

[PCBONEZ]

Re: eVGA 7600GT Cap Replacement Question

ESR is like resistance to ripple.
- Less is better.
[Because the caps job is to short the Ripple to ground.]

The Ripple Current rating is how much Ripple it can pass without overheating the cap.
- More is better.
[If a cap were a resister that characteristic would be called Watts.]

[PCBONEZ]

Re: eVGA 7600GT Cap Replacement Question

.

(which I assume is actually 0.036)

.
Yes.

You didn't give diameters so I dunno which FZ [specs for] you are replacing.

[buriedpast]

Re: eVGA 7600GT Cap Replacement Question

PCBONEZ -

That helps a lot!!! ... I was assuming that all FZs were the same ripple and ESR specs based upon what I read earlier. Obviously, I was wrong and with the information you provided, the 470s meet the old FZ specs.

And as for the diameters, all but the 470s are 10 mm, the 470s are 8mm. It looks like I'm good to go with the Rubycoms ... and for my first recapping.

Thanks a lot for the quick response!

[PCBONEZ]

Re: eVGA 7600GT Cap Replacement Question

No worries.
Sacon's site went *poof* some time in 2008 so the data sheet isn't easy to find on the web anymore.

[buriedpast]

Re: eVGA 7600GT Cap Replacement Question

Well, I got my caps and replaced all of them and boy, did it look sweet when I was through. But, (don't you love the 'but'?) when I powered up the computer with the board installed, no video and then smoke!! That little component at the top right of the board labeled "1R5" has a little coil in it that started glowing red hot!

I don't know what's up ... this didn't happen when the board was installed with the blown FZ caps and the fan still powered up at that time. I guess it's time to toss it unless anyone has some suggestions.

Still, it was a learning experience. A disappointment though, especially when reading about Topcats experience buying a bunch off of ebay and having all but 2 work when the caps were replaced.

[PCBONEZ]

Re: eVGA 7600GT Cap Replacement Question

Bummer.
1R5 means 1.5 and that's the inductor in the filter circuit it and those two nearby caps make up.
Bad caps can stress or nreak other parts.
The bad FZ probably toasted those MOSFETs near it or shorted whatever the load on it is which is presumably the GPU itself.
.
.

[Toasty]

Re: eVGA 7600GT Cap Replacement Question

Solder bridge? Check those 2 caps for shorting. Check the MOSFETs too.

[buriedpast]

Re: eVGA 7600GT Cap Replacement Question

I doubt there's a solder bridge. Although I'm not experienced with this type of effort, I've modded many game systems starting with the PS1 - I'm no newbie to soldering. But things DO happen, so I'll check for that. The question is how to do it? I'll remove the caps, look at the board and measure resistance to make sure the caps aren't shorted. Is that all?

As for the mosfets, do I need to remove them to test? If not, any guidance on what to do to check them out? I seem to recall reading here somewhere that I need to lift a leg and then check for something.

Thanks again. This is just a learning experience / project now. Already bought a new video card, but it would be nice to bring this one back from the dead.

[Toasty]

Re: eVGA 7600GT Cap Replacement Question

Had a nice reply until the damn board wiped it.

Meter the caps. No desolder.

Meter FETs, no desolder. All same reading is suspect. Find thread in here on MOSFET testing.