Well I have narrowed down a problem I've been having with several HD and SD channels displaying corrupted and tiling as if there is a serious decryption problem.
Basically when the problem occurs, it's usually first seen on a higher HD channel (882) where the picture is corrupted and tiled. Then if I go to another channel that was just previously fine, it also shows some corruption, but not as bad as 882. Not all HD channels have this problem, and some SD channels show some level of the problem. I was convinced that the cablecard was getting in a corrupted state and could not decode properly. A simple power reset/reboot of the TV cleared the problem, which occured randonly usually after 3-4 weeks but a few times after only a few days.
Well, it looks like it's not a Cablecard issue, but in the TV. I was away last night and when I got back today my wife tells me that the decoding problem happened again (this time within only a few days of the last incident). The good news is that she left it in that condition so I could troubleshoot a bit more.
So I split the cable and fed analog cable into the ANT 2 port on the TV to bypass the Cablecard and see if the problem existed. I found an HD channel that was corrupting - again not all, but some, which indicates that the problem is in the TV signal processing.
I captured as much info as possible (pics of the channels, checked some of the TV diagnostics which actually showed nothing wrong, etc.) then did a full factory reset which I haven't done before. My theory at this point is that memory or processing software is getting corrupt that affects only some channels. I assumed if there was a tuner problem or hardware, then the problem would be more widespread and could not be reset by a simple power cycle reboot. With the factory reset, I'm hoping it's starting fresh.
I do have the latest 1.2.8 S/W and spoke to Toshiba on Saturday to see if they were aware of any issues, but they offered to send a tech out from the local shop. I don't feel comfortable with someone opening up the unit just yet, so I'll wait and see if it happens again and if it does then I know I'll have to get the TV tech out for a full proctology exam.