Replace backlight on samsung 50" tv - Samsung PS50A466 50 in. Plasma HDTV-Ready

You did not post the model number. The process you are describing is a guess. You should make sure that it is not a power supply issue first.

What is the model number of the TV?

Give it up and replace the TV, they are so cheap you likely have spent more on parts then a new one, and it still isn't fixed!

Fault at its main digital board. Short circuited component/s at it. Contact any service technician; or the authorized service center. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts. http://electronicshelponline.blogspot.com/ In most cases, the main board might have to be replaced. If so, a software [firmware] update too might be necessary.

Hi Rick,
It appears to be a case of backlight failure. since you have replaced all the boards, inverter is ruled out. Some of the LEDs in the backlight array may have gone bad. Fault is repairable, but needs care and experience of opening and repairing the LED panel. Good luck.

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/

Tries tv unplung,replug it back like about an hour later.For the tv to do a resetting itself back to the factory setting.Tv now 50/50 the tv might work as normal again.If the tv dosen't.Tv have a dead 1 or 2 backlight buffers boards have to be replacing.These 2 long backlight buffers boards only job are to provided a tv plasma screen panel for a backlight to see the picture.Tv now the plasma screen panel have no backlight that why ur tv have only audio sound and no picture.No experience in tv repair and never done any electronic board parts replacement before.Best just call many tv shops and explain the tv situation it in and get the best quote prices for parts and labors.Best prices parts and labors should be around $400 is fair more than that as i said shops around for more tv repair shops.

if you can hear sound it is the backlight invertor needs replacing

Ur backlight video inverter board it totally burn PCB,must be replace,might have to check for other boards ,because major burned.

if it is in warranty, call 1-800-samsung for service, if the tv has backlights, then it could be the power supply or main board, if it does not have backlights then its probably the inverter board or T-con booard