Hi and welcome to the site,

Initially, if there is sound but no video displayed, then possibly an inverter / backlighting issue. If however, there is also no sound, then most likely suspect would be the secondary power supply.

Offhand, it would be a hardware concern and therefore would require the unit to be opened up to effect repairs.

Options then are:

• consider a DIY (do-it-yourself) repair if and only if comfortable working with electronic components & circuitry, use of a DVM/VOM, a soldering iron/station and safe practices with electrically powered devices. Access to a Service Manual or at the very least, a schematic diagram would be a necessity;
• should you be uncomfortable with a DIY, perhaps your best bet would then be to consult with and/or seek the services of an authorized Service Center or a qualified professional.

Hello,
Ur power supply board is dead, u know basic electronics’ and soldering? Most of the times, the power supply board just have dead leakages gases capacitors.These capacitors always bulges up on it top,or puff up on it top.Replaced these gases leakages capacitors will get your TV power stable,and work again.Or tries websites like Shopjimmy.com,Ebay.com to buy a whole refurbish power supply board for the replacement.
But you have to do this if you have knowledge of electronics repairs but not contact a well skilled personnel to handle it.
Thanks for asking