I believe this is the movie "Computercide" from 1982. It is a bit later than you listed, but has the scene with the typewriter and microphone. The following Site shows it at timestamp 4:07.
From IMDB
"The year is 1995 and Michael Stringer is the only private eye left on Earth. One day, he is assigned by a woman to investigate Eden Isle, a complex for people who want a perfect life started by an industrialist named Korter. Interestingly, Korter is found on a beach and is 20 years younger than he was before. When he gets into the complex, he is caught in a web of mystery that he might not get out of. "
I remember Donald Pleasence in this movie stating that the egg had become obsolete because they could raise chickens directly. This was a real disappoint to the Detective because he really like eating eggs.
