LG 55LW5700 has sound but just a green luminous screen with black lines in it sometimes hex shaped. On power up the LG logo flashes for a millisecond then the screen goes to green. Is this fixable?

Your LG has a problem on Main board controller. The main board has a graphics driver that give full cycle image going to t-con. Fixing this required main board replacement or repair. Look for a service technician.

LG LED TV has no picture (black screen) but still has sound - can ...

www.tomsguide.com/answers/id-2660992/led-picture-black-screen-sound-fixed.html

Feb 9, 2017 - My 32' LG LED TV has suddenly lost picture! The sound is alright but the screen is pitch black. ... Then completely black but with audio. ... I'm really hoping if I do the right research Ican fix this tv for my husband. .... Take the screen off hit power and watch LEDs if any don't flash its LEDs if they all flash its ..

Without testing that would be a guess.

Take the screen off connect power and watch LEDs if any don't flash its LEDs only needed to change faulty strip if they all flash its probably t con boards.

inverter board issue.

Check out the inverter board that powers the back light leds.

LG 60PZ550 Plasma - No Sound, No Picture - Badcaps Forums ...

www.badcaps.net > ... > Troubleshooting TVs and Video Sources

Sep 15, 2013 - 20 posts - ‎4 authors
LG 60PZ550 Plasma - No Sound, No Picture Troubleshooting TVs and Video Sources. ... I see no change in the screen at any point (no glow). With the rear cover ... I've worked with some electronics in the past, but am new to TV's. I'm sure .... Multimeter on DC 1000V, red on (+) marked, black on (-) marked. Lg 3d plasma 60pz550 i've got sound but no picture
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Sounds like your video is bad or the laptop is not getting power from the ac adapter or battery. Make sure your ac adapter power cord is good.

I am having the EXACT SAME problem. Mine started yesterday.

First--was it working?
Did it suddenly stop?
When you see the LG logo, then it goes away, does the power light turn from green to amber? Sounds like that doesn't happen.
So--if you are getting a signal, you should see something.
If there is no signal, then the power light should change from green to orange.
With no lights at all, I suspect a faulty monitor.