LG smart tv motherboard repair fail/ flashing firmware/ schematics

[tbavcevic]

hi all, i have saved somewhat nice LG 43um7050plf tv from dumpster.

it is in good condition and was working but there was no picture other than on screen menu, i was not sure what was wrong but i think it was main cpu issue.
since i am somewhat in unknown waters with tv-s i had ordered new main board from ebay thinking easy and cheap fix , but mistake was made and i ordered board for 49um7050plf.

when i realized what happened i was still thinking it looks same all same connectors everything looks same from photos it should work right?!

but no, when board arrived it became obvious that it has different connectors that go to panel, but luckily i have managed to remove connectors from original and solder them on new pcb, also some connecting resistors were different so i swap those and also some chip i was too lazy to even google what it is that was empty on new pcb. also eeprom was moved from original pcb to new.

now tv does turn on and backlight turns on for few moments but then backlight turns off but tv is still on and pulls around 7w from wall, remote works for turning off and on again. there is no weird lines on screen for that few moments but there is also no picture.

i am thinking i should somehow flash firmware from old tv and it should work(but how to flash since there is no picture, is it maybe possible to flash over ethernet with like ssh or something) given that there is no mistake with redoing conectors and other stuff new pcb should now be same as original, only i am not sure if cpu is different.

if some good soul has schematics for said tv-s, or knows of where to find them it would help a lot.
any suggestions for what to do to make it work?

thanks for your time and help.