Broadcast transcripts can be difficult to find for many reasons, so here are a few tips that may help:
Because of technology changes over the years, a given program's transcripts may exist in a number of different formats such as microfilm, video, print, or online full-text. Look in the ALICE Catalog in addition to databases.
This is also true for online full-text databases. For example, Lexis Nexis will have different transcripts than Factiva, so you may need to search both.
Often transcripts or audio & video archives can befound at the website of a news outlet. Try the BBC News website, PBS NewsHour, etc.