LG 42LB5800 LED Woes

[kf4rca]

Picked up this 42LB5800 from the roadside. Its a 2014 model. It rattled when I moved it. Turns out all the lenses had fallen off. Not a big deal to reglue them. The screen looked good!
But 6 LEDs were burned out. So, in my quest to replace them I turned to Ebay and ordered a strip of 10. They were listed as cold white, which is what I needed, but it turns out they glowed yellow. Do they need to burn in?
So, I ordered a second set of LEDs from another supplier, that also listed them as cold white. I couldn't get them to turn at all (either polarity).
So, does anybody know the trick to obtain the proper LEDs for these things?
There are 4 rows of 8 LEDs each so changing them all is not an impossibility. Thanks.