EEPhil – 1 hour ago »
I seem to recall that someone once posted a suggestion that if you wanted to do a manual tune, the easiest way to clear out all saved channels was to start an auto-tune and stop it immediately, saving no channels. That would support the idea that auto-tune clears out the old channels first.
As I’ve said in my post #12 above, this is the way I do it on my Panasonic PVR.