That's a classic sign. Ask LG if they will replace these as it's a production defect.
Hi I have a LG 50PC1D that has a white screen on all inputs http://s15.postimg.org/k8c8qdb0r/20150831_153418_1.jpg
I have taken the back off to look I did find that some of the capacitors on the power board seems swollen and black stuff on the top of them.http://s14.postimg.org/r78h7373l/20150831_153533_1.jpg
could this be the problem or is it something else?

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