If you wish to take it to a repair shop it would cost you around $250-$300. You can use http://national.citysearch.com/ and search for "TV Repair"(without quotes) in your area. Or you can use http://www.tvrepairpros.com/If you want to repair it yourself then you should be having proper knowledge about the internal circuitry of the TV.You should also require a multimeter and soldering equipments and schematics.
Take photographs or mental picture of connections with power board before replacing so that it won't be confusing later. I'm sorry there is no easy fix or press-a-button fix. This is an internal failure. If the set has worked fine previously then I guess repairing should be worth it. This is indeed a very good set.
Hope it helps. If you have any queries, feel free to ask.