Hitachi 50HK6100U display issue

[MDY94]

I own a Hitachi 50HK6100U with a display fault. After some troubleshooting, I've found that removing one tcon cable produces a clear image on the side still connected. Removing the other tcon still provides display output; however, this is a heavily distorted image. With both cables connected, only the top ~25% of the screen provides display output which is still distorted. It's only when both are connected that most of the screen no longer provides output. The attached images show the screen with each tcon cable disconnected, and one with both connected. The red line shows where the display cuts off; the 'no signal' box appears/disappears as it moves up/down past this point. I've attempted to multimeter voltage test all of the available points on the tcon and the connected LCD boards; all within range and no difference noted between the left and right LCD board. I've seen other posts starting 'bad panel/backlight' but when each tcon cable is checked individually there is still display output across the whole panel albeit one heavily distorted. Looking for some advice on next point of troubleshooting, if any, or potential solutions. If tcon is the most likely root cause I can likely source a replacement.

[Diah]

i saw many UHD panel with size 50 have same issue at same side of the panel...
try mask only the first 3 pins left at the effected side..

[Diah]

i saw many UHD panel with size 50 have same issue at same side of the panel...
try mask only the first 3 pins left at the effected side..

[MDY94]

So, that absolutely resolved the issue! What do these first 3 pins control; do you know what causes this issue?

[Davi.p]

I wonder why often users are so few smart to show only a miserable flying window with 'no signal' instead of an entire screen image, i know you are probably delighter instead of professional, i'm delighter too but i try to approach with more effort such a fascinating matter,
plus, as a new member it deserves of at least a greeting...
anyhow, for me, it's a bad tcon, hard to find good tcon in the market, used boards often hides troubles..

[Diah]

well its conflict , the side which it show correct image.... if you testing all ceramic caps at buffer boards you will have low resistances, however the bad image side caps have to read normal... so the issue inside the panel at gate transistor., blocking the feed from bad side will help to have acceptable image.

the big questions which i don't know till now the answer .... why only the UHD 50 size effected with this issue !!