To order LED replacement kit go to https://bigdogelectronics.net/collections/for-techs/products/television-led-backlight-strip-repair-kit-includes-50pcs-3v-1w-350ma-2538-led-s

This is a vizio smart tv, model number E70-E3. Over time the picture will begin to dim until the picture gets very dark. The led's in this 70 inch vizio smart tv are connected to the mainboard instead of the power supply board like in 90% of other led tv's. Also unlike other led television's, the tv will still light up with backlight because only the strip with the bad led will not lite up. The strips will actually go out 1 at a time until eventually there is very little backlite. We are going to repair the strips and replace the bad led's one at a time instead of replacing the whole strips. This may be time consuming but it is cost effective and can be done in a good days work.
https://bigdogelectronics.net/collections/for-techs/products/1-watt-lg-type-smd-2-8v-3-2v-led-lights-for-tv-free-pair-of-tweezers