If you assume the replaced parts are good then you replace what hasn't been replaced. Cables and the panel.
This may be a fine example where we need more than one year warranties on the more expensive models.
We've owned our LG 75UJ6470 a little over a year. Recently the screen periodically starting showing black and white vertical lines. We took it in and the technician replaced the power board, main board, and tconn board. After which it worked for awhile but now it only shows a black screen with some kind of backlight ripple effect that will change when we switch channels. The audio still works fine. Does anyone know what could be causing this? I've uploaded some images for reference.