That's a classic case of a power adapter dying, not the socket frying it. Those bricks are basically disposable. There's a Worten department store on Rua do Carmo that should have a universal charger that fits your laptop. Cheaper and faster than a repair shop for sure.
My old Toshiba Satellite went through three adapters in two years. The last one started buzzing like a hornet's nest before it quit for good. I finally just taped the cord at a specific angle to keep it working. That laptop was held together by hope and packing tape by the end.
Ugh, caseyc78 is totally right about those adapters. They're built to fail after a while, not the wall's fault. Just grab a new one and save the headache.