I recently started using the Cisco 8642HDC HD DVR box from Cox Cable. I am now on my third box - they all have the same problem. On playback of a recording, or delay of live TV, the picture will break up regularly (a few seconds of breakup every 20 seconds or so). Unplugging and restarting the box will usually fix the problem for a few hours or a day or so, but then it returns. Watching live TV, everything is fine. The problem is purely with the playback, the recorded signal is fine after I reset the box. The Cox tech support people have been no help - this seems to baffle them. Has anyone else seen this problem, and have any advice?