It depends on the fault,if the plasma screen has failed,then a repair isn't cost effective.
if its a fault on the y sustain or power/inverter, then its a simple repair.
most tech/repair guys only have basic skills in service and power issues,and not the skills to repair y sustain and buffer boards.
most tech will change the boards and these boards can be expensive,
most tech/repair don't want to attempt this repair as most board replacement doesn't always fix the issue,.
you say you have no pic/sound,can you bring the menu up?.
if you can then its a easy repair,
how old is the tv?
Have you had anybody in to take a look at it and diognose the fault and offer you a price for the repair?.
post back on here and I maybe able to offer you more advice, :)
paul
March 2012