Screen goes black but still has sound

The tv that I have is an LG 42LB5600-UZ, but that wasn't one of the choices. The problem is that the television turns on... has a picture and sound, and then in about 30 seconds, the screen goes black but the sound continues. It is the same on every channel. It worked fine last night, but not today.

Originally Answered: What does it mean when your TV has a black screen but is still producing sound? Unplug the power to the external device for 30 seconds. Disconnect the HDMI cable from the TV and move it to an alternate port. Plug the device back in, and power the device back on.
https://www.quora.com/What-should-I-do-if-my-TV-screen-is-black-but-there-is-sound

i have the same problem. and took the battery out then back in. it didnt work. so idk how to help you with that maybe taking out the battery and keeping it off the charge for a day will work.

This is a common problem and a fairly easy DIY fix. You can get the parts from www.TvRepairkits.com

The backlight video board inverter it dead,need a new one.

Broken powerboard/inverter in the screen presuming its an LCD. Can be costly to fix

Capacitors on the power pack are going bad they need to be replaced that should fix the problem.

Sounds like power supply. Probably time for a new tv. You have already got almost 20 years service.

it sounds like your "lamp" is going out look for a hidden compartment.. or in your owners manual to see where its located its an easy fix and costs much less than a new tv