Picture shiver

We have suffered several power outages with the last snow storm to blow through.  Now our HDDVR is acting quirky. The picture quality has developed a "shiver". Every several seconds the picture will slighty tremble. This happens with any channel or recording and also while using the guide. The problem also occurs while replaying recordings. When fast forwarding, the recording skips and jumps with lines and pixalation showing around the tops and bottom of the screen. The sat. dish is clear of snow and obstructions. I have gone through the automated troubleshooting process resetting the reciever and still the problem persists.