LG55LV5300-uA 55" TV just died

Didn't use the TV for a couple months, powered up and ran for 5 mins then powered itself down.
Unplugged it for a bit, plugged it back in, now powering it up causes a steady beeper sound from the back and ONLY the power light illuminates. Then I hear a relay click and the power light goes off after a few secs.
Flashlight test on the screen shows nothing. I could test it on a Killawatt to see the max draw.

TV is 7 years old.

To me this sounds like a PSU problem. I see the PSU for abt $63 on EBAY, used.

Any thoughts?

Something overheating causing a thermal shutdown.........
If so, why overheating.......

Inspect / test all electrolytics on the power supply board - these dry out over time and can cause these symptoms.