Only a service tech may be able to tell. Make the call, see if talking about BAD CAPS along with your story of a new motherboard gets you a free look.
I have a un55d6000. 7 months after buying it the motherboard had to be replaced. The T.V. was making a clicking sound but not turning on. Well 8 months, I am having the same issue but this time I am out of warranty. Is there a cheaper way of fixing this?