From the recommendations I've read, replacing the backlight with your own LED strip is easier than trying to get the backlight of the original TV working properly again (if it's not already); and sometimes even worth replacing if it works as getting just the backlight to turn on can be annoying (not exactly a standard, some take "strange" voltages or are hard to figure out, no specs).
Side note: use 'nice' LED strip lights if you go this route. I did a similar project with a small 19" monitor, for the lensz etc, and grabbed cheapo home Depot LED strip -- it worked about as expected: not daylight/bright enough. I'd reel off specs but the LED strip had none on the box. :-)
Next, larger lens waiting at my brother's house will get a better treatment.
As an aside, it's a really neat project to do, my kids thought it was super cool to help with. Large one will go in stairwell.