I just did this to about 9 TVs at the hotel I work at.
We have LG tv's and the capacitors go bad. As soon as I opened the back of the tv up there is the board and it's easy to see the bad caps.
This is the exact board
Then take a look at the capacitors, if they're not flat and they have a bulge like this picture then they're bad.
Pretty easy from there; some had 4 caps bad and some had only one. Either way BAM fixed the tv for $4 instead of the TV guy charging us $250/per when he was only spending $4