Tv turns on with sound but no video. Backlight working.

If there are at least 2 ribbon cables going from the T-con board to the screen, try disconnecting them one at a time and see if you then get 1/2 picture when you turn on the set.

If there are at least 2 ribbon cables going from the T-con board to the screen, try disconnecting them one at a time and see if you then get 1/2 picture when you turn on the set.

I'll try it and let you know.

Going to open it up today and check it out. Will post what I find in a few hours.

2 cables run to the screen. Removed one and got this:

There was a 50+ set in the dumpster at the free public recycling bin yesterday.
(The guy who runs the place really just likes computer stuff- presumably for gold harvesting.) He throws the TV's away!
I couldn't get it out. I was thinking, where are you guys when I need you!
Ha Ha.

2 cables run to the screen. Removed one and got this:

It looks like you might have a bad board or two, someone once gave me a 55" LG Plasma 3D Smart TV that would give a blank screen when powered up, and it turned out to be a bad board, I replaced it with one someone was selling on eBay that was parted out of a working set that someone broke the screen on (with a Wii controller) and its been working fine since then.

It looks like you might have a bad board or two, someone once gave me a 55" LG Plasma 3D Smart TV that would give a blank screen when powered up, and it turned out to be a bad board, I replaced it with one someone was selling on eBay that was parted out of a working set that someone broke the screen on (with a Wii controller) and its been working fine since then.

Soaybe the entire t con board needs to be replaced.

When you removed one of the cables did you have a source connected to the set ? You should get half an image, not just a light screen. Unfortunately, getting half an image during this test usually means the screen is bad.

When you removed one of the cables did you have a source connected to the set ? You should get half an image, not just a light screen. Unfortunately, getting half an image during this test usually means the screen is bad.

I'll double check. So on one cable, or the other, I should see half? I did try the menu, buttons on remote, etc. And saw nothing.

Soaybe the entire t con board needs to be replaced.

On mine (granted mine was a 2012 vintage set) it only had one T-con board and that was all I had to replace in mine to get it running.

I cannot get a single pic, half screen or otherwise on this. No sound either. Not sure what to do at this point

Try connecting an oscillator to the A/V inputs.
Here's a link to some helpful troubleshooting tips:
https://fliphtml5.com/osspz/lhwm/basic
That link used to be available as a downloadable pdf file but I guess it got removed.

I don't have an oscillator. Is it possible screen is bad or should I order the replacement board and take a chance?

Do you have a vcr that you could connect to the A/V inputs to get sound?
You might be stuck on A/V inputs.
There is also a part 2 to the advance troubleshooting techniques:
https://pdfcoffee.com/qdownload/lcd-led-tv-modification-and-major-repairs-2pdf-pdf-free.html

I have numerous ways of connecting to av inputs. I was using the remote changing modes but didn't get anything

You should be able to get audio either off air or thru A/V jacks.
I'm assuming all your PS voltages are there.
I think you have a main board failure or EEPROM corruption.
Did you read thru the Part 2 download link I sent you? There are some items that I think address your model.

Yes, I'm gonna perform one more test, then I'm gonna replace the board and see what happens.