Yeah, it's a bit hard to follow, but I think I get the gist.
When you say "I used an ordinary/un authorized for it", I assume you left out the word "adapter".
Some adapters are set up with different polarity on the tip--the outside is usually negative and the center positive, but that is not always the case. Sometimes it's reversed, and if you connect the wrong one to the device, depending on the internal circuitry, it can cause serious problems. This is why you NEVER mix adapters, and make sure the one you're using has the same polarity and voltage output as what the device needs. Don't ever assume that just because the adapter fits that it'll be okay to use. This is rarely the case.
To answer your question, I doubt there's really much you can do to fix it. Open it up and see if there's anything obvious, but chances are you won't be able to find everything that's been destroyed. I'd suggest you just buy a new one, and DON'T plug it in with the wrong adapter!
Regards,
Matt