6600GT AGP won't boot - overheated caps?

[edh]

I have a Galaxy 6600GT AGP graphics card like this one:
http://www.guru3d.com/articles_pages..._review,6.html
The caps are all the same as shown in those pictures. It's 8 and half years old so it's not like I'm fussed about it financially but it is a nice little card.

Recently I did a cooler swap to try and bring down the temperatures and noise. I'm very familiar with cooler swaps and have done a number of customised heatsinks. Under testing in Furmark the card was running low 70s and it froze. Now it won't boot and cross testing shows it is definitely the card. The temps are fine so it definitely isn't that the GPU itself is fried, more likely something else on the board.

It was suggested elsewhere that it could be the caps and having not fixed a card at the component level I am keen to try and learn something from this failure, diagnose a fault and fix if I can. All of these components are old so it could be a combination of age as well as stress (Furmark is unrealistic load) that has made something go.

Nothing is visibly wrong with the caps (they are mostly SMD) and I don't have any capacitor tester but something I did think of is that if the caps were to be damaged, they might end up shorting. Testing resistance obviously doesn't give much useful with most capacitors but 2 of them give exactly 4.8 ohms constantly. This got me thinking that maybe these 2 have been damaged?

Is damage under stress testing a possibility? Obviously I'm not definitely saying its the caps as it could easily be something else but if anyone has any ideas on how I could prove the caps are damaged or diagnose any other fault that might be fixable I'd be willing to hear your ideas.

Thanks.

[RJARRRPCGP]

Re: 6600GT AGP won't boot - overheated caps?

Is damage under stress testing a possibility?

Unlikely, unless it's a cheap PSU or extreme OC'ing.

[edh]

Re: 6600GT AGP won't boot - overheated caps?

Well there's no extreme overclocking but this is an old card being put under stress so maybe it is a combination. There certainly have been examples of cards failing in Furmark and similar given the high power loads that they use and some modern graphics drivers will purposefully hold back the card when they detect Furmark being run, ostensibly to prevent damage.

As for the PSU, it's a fairly basic 400W but hasn't given trouble in the past and the total load is perhaps around 170W so not like it is being strained.

I have dug up a Geforce 4 MX440 which has a set of 'spare' 1500uF, 6V capacitors on it so I have some potential candidates for a swap. I know reusing old capacitors might seem bad but it is an old card and for the purposes of learning I just want to see if it would fix it - maybe then I would hunt down some new replacements!

[momaka]

Re: 6600GT AGP won't boot - overheated caps?

That guru3d link isn't working for me.
Any chance you can post picture of yours? If not, does the card look like this?
http://members.chello.cz/dj_studio/p...6600gt_AGP.bmp
Also post some details about the caps. If they are exactly the same as the ones in the link above (i.e. same color and writing on them), then this is unlikely to be your problem as they are know to be very reliable. That said, you may be looking at a BGA issue (i.e. either the RAM or the GPU disconnecting from the board). This is more likely as you said the card was running rather hot (70C is a lot). Before going to that conclusion, I do have a few more questions, though:

- Does the card display anything in the BIOS screen when you boot the computer?
- If the answer to above question is no, then does the computer still continue to run its fans with the video card in there or do the fans just twitch and stop spinning when you press the power button?
- kind of a silly question, but... did you remember to change the old GPU thermal compound with a new one when you did the cooler swap? And when the graphics card was running at 70C and higher, did the cooler feel hot too? (Note: if the cooler is anywhere above 50C, you probably won't even be able to keep your finger on it.)

[spleenharvester]

Re: 6600GT AGP won't boot - overheated caps?

What was the old cooler and what was the new one? Maybe the new one didn't cover up vregs? I killed an 8800 this way.