SONY DVD HOME THEATRE SYSTEM. DAV-HDZ235

Last week I'd a short-circuited with the cable from one of the speakers.
Accidentally the cable touched the electric connection and it sparked. And part of the speaker cable got melted on the connection. I already opened the Amp and nothing inside looks burned or with signs of short-circuited, no even the only little fuse.

I removed the short-circuited part of the cable.
I disconnect and connect again all the speakers, and specifically in that connection now you can hear a loud popping, and still the "protector" thing is on the display.

So what do you guys think it could be the problem???? And how could I fix it??

Cheers!