But first I suggest you to make exlink cable and check what's going on terminal window. Might here isn't that bad as you say...
But most of errors are critical.
Good thing is that you`re getting any response from TV at all
I guess here is preFEB (old ) firmware on board and if i was you, i tried to repair TV over u-boot and console.
Step by step:
1. access u-boot and reflash kernel (if you can access console -kernel is boting - this we can see in logs, then skip this step)
2. access console over exlink (after success kernel boot) and reflash exe.img and appdata.img
3. switch to reflashed firmware.
I don`t know, perhaps this don`t help at all or maybe you get errors while re-flashing (if here are some hardware problems - errors indicating to this), but we will know that here isn`t anything else to do and mainboard replacement is case of choice.