Adam's/PR's Accent

[Doc]

While the character of Adam was of course a Yankee, we all know that PR hailed from the South. I imagine, that being an actor, PR had to try and lose his native drawl quite early in his career. However, although his vocal characterisation as Adam is quite convincing, there are times when I think his southern drawl shines through, particularly in the first two seasons of Bonanza. A good example for me is the episode 'A House Divided', when he storms out of the front door of the Ponderosa and tells his father to leave him alone. Personally, I really like it when his native accent creeps in (it's so sexy), and I was wondering if anyone can think of some more instances?

Also, does anyone know if there are any clips of PR just speaking normally? I know he uses a southern voice in Loneome Ride, but I often wonder whether he exaggerated it for the role. He doesn't seem to have a drawl in TJMD, which makes me wonder whether he lost his drawl by that stage.