Chosen Solution

My 55” UN55JU6500 screen suddenly went very dim and now blinks rapidly. There is still a picture however, you can barely view it due to the dim lighting and screen blinking.

This is a LED backlight TV and it would seem there’s a fault in the power feed to the LEDs. Most likely this is a bad electrolytic capacitor (see https://wiki.restarters.net/Basic_electr...), which is a fairly easy fix if you can do a little simple soldering.