loose connection possible. But a loose connection would not repeat an on/off cycle 2 on/ 2 off………..
each section of the screen is driven separately. It sounds like the circuitry for that section has a problem.
It is probably fixable by replacing the driver board for that section (though the board may include all sections). You need to look at whether it is worth the part and time/effort. The part might be used (cheaper) and the rest of the TV my have a smoldering problem (bad capacitors). There is no warranty on anything. New TV will have some kind of warranty.
There may be a Sony specific community forum that will have the exact problem and more info.