How to test LED backlight without disassembly using 9V batteries

First: Do this at your own risk. There is high voltage involved in this and you should know what you are doing before attempting this.
This was done on a 2017 Samsung LED TV Model UN55J6201AF.
This video shall help you identify the source of your problem. I struggled to find videos that help identify the broken part, so I hope this helps someone with the same struggle.
There are other videos available that explain very well how to replace the LED strips, personally I recommend this video how to replace the LED strips: • Samsung 60" LED TV - L...