LG CX 77 reboot loop with black screen

Hi everyone,

A few months ago, my 77CX (bought in dec 2020) started behaving strangely: when I tried to power it on, the LED would blink, it would make a noise, reboot, and then it would work. Sometimes it would cycle twice. But once powered on, it would run fine, even for a full afternoon.

Recently, however, it stopped powering on at all. It just keeps cycling: LED blink, noise, reboot. After unplugging and plugging it back in, it does the same thing again and again.

I’ve made a video of the problem so you can hear the sound and see the LED blinking (if the video does not work, you can watch it on my reddit post).

It’s out of warranty, so I’d like to repair it myself. I just hope the panel itself isn’t defective. Any tips on how to diagnose if it’s the power board, main board, or the panel?

Thanks.