Recommendation from the B4D Forum:

“Felix Eletrônica e Informática is an IT store in Asa Norte specializing in computer accessories with the main focus on cables, converters and adapters. They have a huge range of audio-, video-, data-, power- and converter cables.

In addition, they can custom build any cables or converter you require. That comes very handy if you need a non-Brazilian power cables replaced. They also have a computer repair section.

The owner speaks very good English and is very helpful and knowledgeable.”