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#1 |
Member
Join Date: Mar 2018
City & State: SK
My Country: Canada
I'm a: Knowledge Seeker
Posts: 24
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![]() My friend has this EVGA GTX770 GPU that, after 7 long years of use, is now starting to act up with artifacting and causing random black screens requiring a hard power down.
I decide to check the caps, since I've revived other GPUs by replacing bad ones. Physically they all look fine. These are all very low ESR caps, like aluminmum polymer <=10 mhom and tantalum polymer in the range of 20-30 mohm. They all test fine ESR wise. They're grouped as follows: 4x 270u 16V Al-polymer 3x 100u 16V? tant-polymer 9x 330u 2.5V tant-polymer 4x 470u 2.5V tant-polymer The odd thing is, all 9 of the 330u range from about 208u to 247u. They clearly have "330" marked on them in large numbers, but they all seem to average to around 220u. The ESRs all test 20 or 30 mohm. Does anyone know if that's a sign of them failing, or are these actually 220u caps in disguise. Last edited by itachi; 11-03-2021 at 11:28 PM.. |
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#2 |
Badcaps Veteran
Join Date: Aug 2005
City & State: San Jose, CA
My Country: USA, Unsure of Planet
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Posts: 3,370
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![]() Polymer caps don't have a liquid electrolyte that can evaporate over time. BTW, the dielectric in an electrolytic or polymer cap is not the electrolyte or the polymer. The dielectric is a layer of aluminum oxide on the surface of the anode foil. The electrolyte-soaked paper or polymer is a conformal conductor between the cathode foil and the aluminum oxide surface.
Some ultra-low impedance electrolytics have had problems with the electrolyte attacking the aluminum oxide layer, but I've not heard of problems with the polymer affecting the aluminum oxide layer.
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#3 |
Great Sage 齊天大聖
Join Date: Dec 2009
City & State: Europe
My Country: some shithole run by Israeli agents
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Posts: 26,430
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![]() maybe they are breaking down slowly because of the ripple current.
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