LG 55LA6908 half screen has tint

[ducttape]

Hi guys,
I just replaced a failed main board in the TV with what it appears a new unused board. Tv works great now, with one problem. Exactly half of the screen has a different tint (see image). Im not sure if that problem was there before swapping the board (previous issue was unstable operation, random turning off, dead hdmi ports - probably bga issue).
Any ideas? I tried cleaning and reseating the lvds cables on the main board side with no difference.