I have this sound card from my old broken computer, which I took out. My old computer died probably because I switched the voltage (I live in the united states, so the voltage should be a decrease) or the motherboard just fried. All that time my Creative blaster audigy SE sound card was inside (it is a old card). I noticed that the metallic (whether it is copper/aluminum, I don't know) plate covering the hole that you would plug your speakers into (behind the plate that fits into the expansion slots), shows burnt colors all over the copper color. The holes have four colors; orange, black, green, and blue, the green one is covered by green plastic as the other metallic plates are exposed so I can see the burnt color. Will the sound card still work? I don't see any other signs of damage.
Here is an image showing the places with burnt colors (the plate in the picture looks shiny and white, but for my sound card, they are copper color, or at least I think it is supposed to be, unless it is caused by the burnt). This is not my own sound card, but it is the same type and/or model:
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I don't think it would burn so quickly, it's more probable to be oxidation or something similar.