LG 42LB650V Compatibility Query!

[Varoshiotis]

Hi All, I hope someone can point me in the right direction!

I offered to help a friend repair his LG 42LB650V 3D TV; it powers ON, the red light at the bottom of the screen comes ON, then it flashes a few times on pressing any channel on the remote and that's it. (I think the TV then switches OFF). NOTHING is ever displayed on the Screen and my friend assures me that the screen is working (& has not been bashed or broken).

I managed to get a 'broken screen' TV (again Model 42LB650V) and replaced the Power Board - no joy (behaves as before).
I wanted to then replace the Main Board BUT found out that the two TVs (despite having the same Model Number 42LB650V) differ!:
My friend's TV (the one I'd like to repair) Main Board has Markings: EAX65384004 (1.5) & EBT63439306.
The 'Broken Screen' TV has Main Board Markings: EAX65384003 (1.2), I think the other Part Number is EBT62383444.
The Two Main Connectors on the Main Boards are different!

I continue to try and find a cheap Main Board for sale but to date have not succeeded - I have found some for £75 - 100) but hope there is a cheaper option and I continue to search!

In the meantime I wonder if there is another workaround - i.e. is there a way that I can utilise the working screen TV but replace other parts (Main Board + Others) from the Broken Screen TV? Or, are the Screens also different and so my only option is to purchase an expensive Main Board?

If so, am I constrained to searching for that exact Main Board (eg. EAX65384004 (1.5) & EBT63439306) or are there additional boards that are compatible?

I hope someone can please advise me?

Thank you.