Hello
There are tow reasons for this fault with Hundai sets. The first one is with "Reset", and the second one is with its power regulator circuit board. As the set is now in OFF condition and no screen is available to get a reset option, the fault will be due to the power regulator board itself.
Open your TV, and locate the power switching regulator board. It can be located very easly, as power cord will go diretly to it after the main panel ON/OFF switch. I'll give you a picture of the picture of a typical power board here. Usually these board are irrepairable, and must replace it as card basis. Check for any bulged capacitors, as shown in the picture, in the power board. If so; replace them. This is the only repairable thing with these type of boards. If there are no such capacitors seen, unplug out each pluged in connections on this board one by one and reconnect it. If any loose connection proble is ther, doing this will rectify it.
If nothing helps you, replace the board. This board will have a number printed on it, which should be noted when buying anew one. The board can be bought from most of the electronic sparepart shops at your town. It can also bought from the Authorised Service center for Hundai also. OK.