My power shows good but no picture

Back - light problem. Check and replace damaged component/s at its back-light inverter board, or replace this board as card basis. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts. It will be best to replace the inverter board as card basis.
http://electronicshelponline.blogspot.com/
In some models of LCD TVS; the backlight inverter and its T'Con board will be a part of the panel itself, and will be a built-in type inside the LCD panel. If so, they can't be replaced. In this case; a panel replacement is the only repair. For some other models, the backlight inverter section circuit will be a part of the main power supply regulator [SMPS]. To such sets, the power supply section circuit too should troubles shoot. Contact any service technician. The circuit will differ with models and versions.

This is likely a blown power board with secondary capacitors blown and not the primary. If your power board shows green LED and no picture then there is no power really going to other boards.

Check the power board for blown caps. This can be an easy fix and low cost if you are handy with a soldering iron and can replace caps.