Could this be Captain Z-Ro from 1955?
Scientist Captain Z-Ro, working in his remote laboratory, safeguarded mankind and history from impending harm. He had a time machine, the ZX-99, both to view history and to send someone back in time. Each week, he and his teenage assistant Jet would view an episode in time and inevitably see that some event was unfolding contrary to history (e.g., King John not signing the Magna Carta). Captain Z-Ro would then send Jet back in time to intervene and ensure that history played out as originally recorded.