Last week I started seeing pixel tiling on my Phillips DSR7000 on as many as seven channels. After DirecTV had me restart the TiVo, it also powered on and off. The hard drive replacement I ordered and installed didn't solve the pixel problems, so I ordered a replacement for the DRS7000. The next day, the pixel problem stopped appearing, but anything I tagged to record recorded exactly seven minutes late. I checked and found that the TiVo had the correct time. Then that symptom disappeared. Has anyone ever seen the pixellation come and go?

The replacement unit is here, but I'm wondering if there is another problem. Has anyone seen these symptoms or, better yet, figured their cause(s)?