I forgot to mention the full model code is un58j5190afxza, though they also list un58j5190af and un58j5190. Also, I tested the power cord with another tv and it worked fine, so the power cord isn't the culprit.
A couple of days ago, my grandfather was watching his tv when it shut off. It won't turn back on and has no red power light indicator or screen light at all. It happened during a storm, so it might have been a power surge (I was on vacation so I don't know how bad or if it even came close to his house, so it might have been a coincidence it went off then). He went to Best Buy to see what was wrong and two people said "the main box" or something was likely the cause. He ended up just buying a new one and giving this one to me, as he knows I like to fix things. I took it apart and did some research to and from what I got it's likely the fuse on the power supply board, or the board itself. I tried to use a multimeter, but it doesn't have a continuity mode and it's not digital, so I gave up on that (It has RX1, RX10, and RX1K ohm modes, and using RX1, it said 0 ohms). The motherboard looks fine, though underneath the main chip with a heatsink on it on the other side of the board, the color of the board is ever so slightly darker than the surrounding board. I can't really figure out if the fuse or resistors are fried on the power supply board and the capacitators are fine, but there are spots on the top of the board that are dark brown (In the picture), where it maybe is fried. I'm not sure exactly what's wrong at this point but I think it's the power supply board, so any ideas?
https://imgur.com/PNx6kkM
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