Samsung LN40A500T1FXZA audio but no picture - Samsung LN40A500 LCD TV

If you've switched on your TV and the sound comes through fine, but you're not seeing any picture; there are 3 potential issues. No video with normal audio on a Smart TV will the result of one of the following issues: A connection issue; the most common problem. ... An issue with the device connected to the TV
https://www.samsung.com/au/support/tv-audio-video/my-tv-has-audio-but-no-video/

sounds like a bad panel. Did you do a short check for the driver ics on the flat flex?

Perform flashlight test to see if the problem is with the backlights inverter board.

If you wish to get some details; check the site linked here. Pull up older posts. Surf the site with patience. http://electronicshelponline.blogspot.com/
Faults & possible causes to LCD screen are given with illustrations. You can get an idea about the fault to an extent.

Sounds like T'Con board fault. If you wish to get some details; visit the site linked here. Pull up older posts. Surf the site with patience. http://electronicshelponline.blogspot.com/
Faults & possible causes to LCD screen are given with illustrations. You can get an idea about the fault to an extent.

The set will need to be properly diagnosed to narrow down the problem. You could be looking at a bad inverter, bad CCFL lamp, fault in power supply or main board.

The backlight inverter which is also part of the power supply needs to be replaced. If you feel comfortable you can replace the blown capacitors on it.

If you need further help, reach me via phone at https://www.6ya.com/expert/steven_a67ead41eb5fc62a

The tv have 2 long LCD inverter boards are dead.These 2 long LCD inverter boards help the tv LCD screen panel to have a backlight to produced a picture.That why u have audio only no video.Tries websites like Shopjimmy.com,Ebay.com to buy those 2 long LCD inverter boards for the replacement.

have you used the picture-in-picture function and swapped the sound by anychance? from main to sub?