LG 42LM620T-ZE

[EVILMRB]

Hi this TV works for about two hours then I get a thin black line at the top of the screen (as seen in pic 1) and then straight away it drops down about a inch (as seen in pic 2) but at the same time the whole picture jumps at about every 8 to 9 seconds.
Any help would be very helpful, and I have uploaded the service manual for this model on this site if anyone needs it.