First of all (referencing the manual) the Static Precautions on page 1-4 should be read through, and observed at all times when dealing with components (as opposed to when dealing with fasteners/screws or case parts, which being vinyl and non-electronic, are exempt from those precautions.)
Disassembly/reassembly is section (3) of the manual, page 31 of 79 as viewed in a PDF file viewer application.
The first thing you do, the very first, is unplug the TV! and leave it that way for the duration, and in fact it's safer if you delay opening it after unplugging it, for a half hour or so.
Place face down on a padded table, remove 6 screws that hold the stand on, remove the stand.
Then remove 8 case screws (see illustration.)
Remove the Rear Cover (minding two sharp spots on it.)
At which point, a pause... I need to find what the module that contains the LED or other lights that has (mostly) gone out, is, part # ***** how to get at it, etc.