Mrs Daley mentions The Fonz as well as other TV characters. Mrs. Daley was played by Marion Ross who co-starred in Happy Days (1974).
At the time this episode was aired, whenever a TV station was having trouble with its broadcast, the techs would put up a card and say over it that the problem was at the station and not with the viewer's TV set. The statement was standardized across stations and began and ended with "The trouble is not in your set." it was commonly referred to in American popular culture, for instance the opening of The Outer Limits.