I have a LXI tv (Sears) model CTC186/7 that the picture curves in from both side. I suspect a loose conncetion/cold soder because when I removed the back to verify the chas number I tapped on the circut board a couple of times and the full pix returned for a few days. Tapping on the board no longer helps.
you could try resoldering the pincushion circuit board.it is usually mounted oh the h. o/p heatsink, a small board. if no bad connections, check & repair any bad connections on the main board.
