Could be electrolytic capacitors and or something else on the Power supply board or a short on another board upstream . It sounds like the PSU isn't passing the ( Power On Self Test ) and shutting down due to any of the above causes .
Note : Sometimes a set can run a while then shut down also when a part heats up and drifts out of value or just shut down immediatly at power on .
You can find videos about replacing Samsung TV capacitors all over Youtube and the correct capacitors are widely available they even have capcitor kits listed by TV models on Google ,Amazon and Ebay in some cases .....along with fixing a lot of sets that way I fixed one recently for some one for $9.00 in parts (4 capacitors) and that included $5.00 shipping from Digikey ,a shop will charge you ~ $300.00 for the same thing .
I Just fixed an open circuit play button on a fairly new out of warranty $395.00 Maschine Mikro midi Controller /Drum Synth today with a dab of silver/epoxy conductive circuit repair paint.