My problem ended up being a bad TAB bond to the LCD panel itself. See the last photo at:http://home.myfairpoint.net/~langhof...um_1271775431/
The problem area is in the red circle. TAB = Tape Automated Bond. The 4661 LCD panel has a couple dozen TAB connections, each with numerous parallel connections. Each TAB connector is just a thin ribbon, and touching the bad one with a non-conducting probe (a chop stick in this case) caused the lines and shadowing to go nuts. Touching the other TAB connections had no affect.
Taking apart your TV is dangerous, and powering it up while it is apart is more dangerous, so I'm not recommending you try this. I did not try this until the TV became unwatchable and I had resigned myself to buying a new one. With the arrival of fall and cold mornings, the lines had become large black areas that would linger through an entire show sometimes.
First, I removed the TV back, then the base (including the plate it attaches to), speakers, plastic bezel & power switch, and side panel jacks (screws only; I left the electrical connection). This leaves the LCD itself. To get at the TAB bonds, I removed the metal frame around the LCD panel. Once the metal frame is off, there is not much structure, nor anything holding the LCD to the backing other than the TAB bonds themselves. I then propped the LCD against a wooden speaker on a wooden floor. I removed the power switch from the bezel and reconneted it to the main board so I could turn the TV on. I also reconnected the speakers just in case the audio output requires a load.
After confirming which TAB bond was bad, I applied a piece of non-conductive foam wrapped in electrical tape over the area circled in red. It was just thick enough to compress the tab bond when the metal frame was re-installed. The picture has been perfect since. Good luck..
This is were I read a simalar issue concerning a tab bond issue?