This may or may not apply to you but on my Dish DVR, all you had to do to see previous programming was to press the "rewind" button to scroll backward. Mine does 30 minutes max but it's an older unit.

Another thing to keep in mind is that if your box has two tuners, the "buffer" is only recording on the last two channels that were viewed. Once you switch channels, the buffer starts over. Again, this is my older setup but the theory may apply here as well.

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-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250