Hello, I'm TV Tech1 and I'll be working with you to identify and help you resolve your problem. It sounds like you have an LCD TV set, if those lines run from the top to the bottom of the TV. Is that the direction of the lines, or are they from the left to right side?
Have you found your TV's model number and brand name on the sticker on the back of the TV set? We'll need to get that.
This picture shows a good example of where that sticker is and how they list the model number on most TV brands.
The lines go from top to bottom and range in colours each time it happens.
Serial No. AGHR3S2P200090M
TV is a Samsung
The lines are not on the screen permanently the are intermittent with no warning so the tv menu is visable. They appear, the tv switches off then after a few seconds comes back on.
I can watch the tv normally just intermittently it will do this. It can happen at any time but I would say more so once warmed up
Ok, that helps. If it failed MORE when the TV is just turned on, it would be power supply related, but if it fails MORE when it's warmed up, the TCON is getting hot and failing at that time.
I have a picture here, showing you how to remove your TV's rear cover, where the TCON is, and the problems that can make that TCON create lines. I recommend you follow the fixes listed in the picture first. The LVDS cable has two little pushbuttons you need to press to unlock it so you can plug and unplug it.
See picture --