Is it permissible to accept payment for establishing a company that sells quality control monitoring systems for television broadcasts, and would I be sinful if the company sold its systems to corrupt channels?

Selling televisions is permissible in principle, but since it is common for television channels not to be free of corruption, selling them falls under aiding in sin. "The ruling is based on what is predominant, and what is rare has no ruling." Therefore, it is not permissible to sell these devices or to assist in establishing a company to sell them as long as their predominant use is unlawful. As for taking wages for the work, there is no harm in it because the work itself is not forbidden; rather, it became forbidden from the perspective of aiding in what is unlawful.