My XL4, which has admittedly been in use for six years, has begun to show an interesting failure mode: After coming on, and with me able to go through all four available feeds, use the guide, go into My shows, etc., will, if I'm watching live cable feed, intermittently go video blank, and none of the control buttons work. The channel I will be watching will come back, after I get a screen display that it is loading all the channel information. After a bit, the buttons all work again. Is this a software, TiVo hardware or a cable card issue? Has anyone else seen this kind of behavior before? I have run several of the diagnostics, cable/ethernet feeds all check out fine. Oh, and it DVR's just fine! TIA for your thoughts on what's happening!