I have horizontal lines on part of my TV screen.

I recognize that this is an old question. Horizontal lines are almost exclusively caused by failed Gate drivers on the panel. They are part of the panel and can not easily replaced (requires special equipment). You can always check the small ribbon cables that connect from the driver board (part of the panel) to the LCD panel itself. Those flat ribbon cables are bonded to the panel. Push on the ribbon cable that corresponds to the location of the line. If that line changes or disappears it is a failed bond. Should the line be unchanged it is the actual gate driver for that region which has failed. this is not a board failure, but a panel issue.

"One thing you might want to try is give the TV a few wacks on the back. Just lightly hit the Tv a few times on the back all around, and see if that fixes your issue. if it happens to, or when doing it you see the lines go away but come back right after you hit it, it could be a loose connection, If it doesnt, report back and we will explore other options.

But sometimes hitting it actually works!"

I was told many things it could be the panel or t con boards so I did some more research and it always led to same thing so a local guy who repairs tvs told me before paying for parts or anything like that take the back off and disconnect all the connections wait a few minutes put them back on and my tv works again.. my problem was when I would turn my tv on after a few minutes the screen would jump around with horizontal lines then go away and come back after a few more minutes, what can cause that is loose cables inside the flatscreen itself or even dust that builds up can interfere with the picture I highly recommend you trying this before paying to have it repaired with new parts or throwing it out as my tv is bran new 60 inch flatscreen RCA it may seem like alot to do and technical but I'm not a technology person it just takes 15 minutes out of your time to take screws out disconnect cables put them back on and put the back cover back on and from doing that my tv is back to normal

Hello there! I had the same issue with my Sony Bravia Tv and I found a solution on my tv manual. Check your tv coax cable and remove it. If that resolved the issue meaning you need to change coax. If your coax is rated 300 ohm, used 75 ohm instead. So far, i dont get the line anymore!

My Tv is a Chinese brand and the line appeared after 3 months. The problem is I move the Tv everyday from room to room so something came loose. I connected the ribbon connector firmly and the lines disappeared but once I reassembled they appeared again. I turned the TV upside down and the lines disappeared. This tells me that the ribbon itself is no longer secured. I tried using electrical tape it didn’t work only made it worse.

I had fine horizontal lines and grainy screen with shadowing on my 55” LG LED TV. It was about 10 years old. Took t-con board and data board out of TV and preheated my oven to 210 degrees Celsius, baked them for 10 minutes exactly on a pizza tray. Put TV back together. Working like new again. Vic H.