The Bad Son - S8-E3
Audio problem: Frasier is standing in his living room talking to Niles. We hear a knocking or tapping. As Frasier is expecting his date, Miranda, this might make sense, but they do not seem to hear it and make no move towards the door. A short time later the doorbell rings and Frasier's date arrives.
Answer: It equals the record of James Arness of "Gunsmoke" for the actor who's played the same part on TV NOT in a soap opera. If you include soaps there are two main contenders - William Roache, who's been playing Ken Barlow in "Coronation Street" in the UK since 1960. Don Hastings has been playing Robert Hughes in US soap "As the World Turns" since 1960 as well.