Lacking a picture and if it isn't the main board or TCON or an LVDS connection ,the LCD Panel Cell is bad IMO .. if you could host a picture somewhere that would be good
If it matters here I can bench and repair LCD TVs ,they are simple to diag. .
I have an electronics education and have replaced LED lamps inside TV panels too like my 55" 2015 4K HDR Sony LED bar I just did along with some board level repairs in it to get DC current to the new salvage LED bar
The old LED bar overvolted the LD board and the T3 power transistors that smoked open when the that LED bar was failing .The LED bar tell was partial screen dimming and my DVM to pinpoint the faulty board parts after it went all dark and in a boot loop I had to reload the firmware with a special procedure to foix after the othert stuff was fixed ,
Tomorrow I finish repairing and restoring a nice vintage vacuum tube 1960's Hallicrafters gen. coverage AM shortwave radio I found on ebay and rotate it in and see how it shakes out and if it stays in here with my 2016 Grundig before I score a 1937 or 1938 Zenith short wave 10-15 tube big glass round dial project or radio chassis that definitely will stay
Some late 1930's Zenith radios and a few others could easily cost as much as a new Buick back then and hold up to a modern $1,000 -$1500 ICOM digital com. radio on AM shortwave just fine and beat the pants off the 1960's Hallicrafters I picked up and my Grundig .too
1937-1939 was the pinnacle of radios like that and in general for a consumer furniture grade gen coverage AM/SW radio like that .since then.
everything else LIKE 5 TV ,4pc and sound is 2013-2016 or newer at the home like the 4K HDR 1000 2016 Samsung SUHD 55 KS 8000 in here and this PC and the grundig Shortwave a 5.1 ELAC speakers and little older Sony ES AVR
The vintage stuff is not digital at all and I came up on all that and it's actually much more difficult ,interesting and challenging to diag and repair or upgrade than a 2017 4K HDR TV or PC . but I like the TV's and most of the other stuff better now outside of a few old radios for what they do and tinkering .