TV or cable techs, can you help?

I have been having a problem with my TV for a month or two now. The video frequently pauses while the voice keeps going; sometimes the voice stops also, and on its own the voice cuts in and out. I also get momentary pixellization. I believe this is called "tiling." I called Comcast and the repairman came out and said the outside wires were all corroded, and he replaced them all, plus did a few things inside the house. It didn't help at all. When I called Comcast back to tell them it didn't resolve the problem, the woman I spoke to was very rude and said everything that could be done had been done. I asked her if I should pick up a new cable box, and she said, "Sure, why don't you try that." Unfortunately, Comcast has moved from our area and there does not seem to be any office nearby. Can someone offer any suggestions for other things I can try? Do you think it is definitely cable, or might it be my TV? Our TV is not that old...less than 10 years, I think. It is not HDTV, but it is digital. Thanks in advance for any help you can give me.