Below are some of the career pages from companies with LA positions. Check their sites periodically since these are updated by different departments. Some of these sites will also have internship opportunities.
A+E Networks: A&E, History, Lifetime, LMN, FYI, Viceland, Crime & Investigation
Discovery Communications: TLC, OWN, SCI, Discovery
Disney: ABC, ESPN, Lucas Film, Marvel, Pixar
Time Warner: Warner Bros, HBO, Turner/Cartoon Network/Adult Swim
Viacom: BET, CMT, Comedy Central, MTV, Nickelodeon, Spike