I have an NVIDIA GeForce 7300LE graphics card that's having problems (see here), and I heard about baking the card to restore old solder joints.
The thing is, this involves putting the card in the oven at 385 oF (200 oC) for 10 minutes and the capacitors on the board are rated to 105o C operating temp and I don't know if they would be damaged by the high temps.
Would the 385o temps damage the caps or plastic connectors on the board, or would it be fine?
Thanks!
EDIT: Well, since I needed to replace that card anyways, I figured I would try it and see:
- I heated it in my toaster oven, to a max temp of 250o C for about a minute, and an average temp of about 200o C (not counting warmup and cooldown)
- the board was not damaged in any way, and all the plastic connectors survived, but…
- when I plugged it back in my computer, I got crazy patterns of flashing lines across the screen
I think that the temperature might not have been stable enough to keep the capacitors from frying (it was a toaster oven, I guess I should have used something with more of a good temperature gauge) Ah well, I guess it was worth a try. Time to go to the local computer parts shop and get a new graphics card 🙂
Best Answer
It's been pointed out that the temperature should have been stated as 385 F and not 385C. That makes a substantial difference. I'd STILL recommend the test that I suggest at the end as a guide to what to expect. 385F = 196C
The formula I gave suggests a 5% reduction in lifetime under those conditions over 8 minutes. That would almost certainly be so far outside the sensible range of use as to ber very very very approximate - but shows how extreme even 196C is compared to 105C.
Unless the board is otherwise a complete write off, don't even think about it.
Apart from the effect on the capacitor the process will cause major damage to other components - see below. Aluminium "wet" electrolytics have a electrolyte with a boiling point roughly the same as water has. While some capacitors are made to withstand temperature will above water boiling point, most aren't. There is an extremely good chance of inflicting major damage to the capacitors.
There is a lifetime calculation formula for capacitors which almost certainly does not apply here - but "for fun" it predicts that the lifetime of typical psu caps would be about
2000 hours x 1/2^((385-105)/10) = about 1/500th of a second :-)!!!.
They'll last a bit longer than that, but you get the idea, I'm sure.
BUT if you REALLY want to try, see the suggestion at the end.
Even if it is wholly dead there are other things you can do which have more chance of fixing it.
What you propose has a very good prospect of doing major permanent damage.
Any plastic component on the board will melt below that temperature.
Of all the plastics you are liable to encounter only two have continuous service temperatures above water boiling point (100C / 212 F) - those are PTFE and PEEK and you will have little or none of either on your board. (Just maybe some PTFE in a connector).
Table of plastic characteristics here
Resoldering all the solder joints that you can get to MAY have a better effect.
There is no guarantee that the page you cited tells a genuine story. I have seen pages which make the most outrageous and certainly untrue claims complete with step by step instructions on how you too can waste time and money following their example.
Simple experiment:
Take a board that you do not value at all. Ideally with enough connectors etc to be vaguely similar in content type to the one you are thinking of incinerating.
Try it in the oven at the temperature that they suggest for the time that they suggest.
Report back
Added:
See this directly related article
Robustness of Surface Mount Aluminum Electrolytic Capacitors When Subjected to Lead Free Reflow