We had a Samsung TV that did something similar. Fortunately, I had bought extended 5-year warranty for it with a third party. Called them up. They sent a repair person who opened the TV. It's amazingly compact. All the electronics were in a couple of low profile circuit boards. He pulled the connectors, popped off the boards and snapped new ones in. It was surprisingly easy. You can take the whole thing apart with a screwdriver.
The whole thing is integrated. There's no way to fix an individual feature. It may be the power supply is not functioning right, but you have to replace the whole motherboard with the power circuitry. You can find spare parts on ebay or through authorized repair people.
In our case, they swapped all the PCBs twice and it didn't fix the problem. The insurance offered to swap the TV with a newer one but the specs were much worse. They ended up refunding the purchase price. Got an LG. Much better color quality IMO and hasn't failed yet.