Can turn tv on picture comes on and then black screen can here sound and change channel

It can be dead 24vdc or dead backlight inverter boards.
Look for cold soldr joint in the 24vdc power supply section especially around the gray cap legs.
See my pictures here: http://s807.photobucket.com/albums/yy352/budm/Westinghouse%20LTV-32W1/

Please learn about troubleshooting LCD flat panel TV here:
If you are going to DIY and have proper tools, electronics knowledge, and know safety precaution then please read on:

Please see my basic troubleshooting guide here:
http://www.fixya.com/support/r5093881-lcd_flat_panel_tv_troubleshooting_guide
http://www.fixya.com/support/r6150077-basic_lcd_monitors_troubleshooting
Failed TV and Monitors: http://s807.photobucket.com/albums/yy352/budm
Learn about bad caps: http://en.wikipedia.org/wiki/Capacitor_plague
Capacitors kit: http://lcdalternatives.auctivacommerce.com/Default.aspx he can make you a set of caps.

Parts: www.shopjimmy.com

Please post back what you find.

Tv turn on now,have a flashes a picture only a few sec. than picture died and have sound left ony?Yes,than ur tv have a 1 or 2 long boards call the LCD inverter boards are dead.These 1 or 2 long LCD inverter boards help the LCD screen panel to have a backlight to produced a picture.Tries websites like Shopjimmy.com,Ebay.com to buy those refurbishes 1 or 2 long LCD inverter bords for the replacement.