Why does the monitor lose power after being turned on for a few seconds? (See the video recording)

The monitor model is DELL U2419H.

After the power is turned on for a few seconds, the screen goes off. The On/Off light at the bottom right corner goes off too. Nothing happens if I turn off and turn on the power again.

However, the next day, when I turn on the power, I can see the screen again. But again, it lasted only for a few seconds and there is no On/Off light.

https://reddit.com/link/1dncsvk/video/k1b7xmfqni8d1/player

I disassemble the monitor and check the power supply board. However, I cannot see any damaged/bulged capacitors. Has anyone had a similar experience before?

https://preview.redd.it/r3q0640ioi8d1.jpg?width=2268&format=pjpg&auto=webp&s=4ab6219fd7be534b70e0cec521d501f0de4c7642

https://preview.redd.it/tspsn50ioi8d1.jpg?width=4032&format=pjpg&auto=webp&s=423b996e1d94b320ee2138c64ccc719df68be48c

https://preview.redd.it/fkn6k50ioi8d1.jpg?width=4032&format=pjpg&auto=webp&s=a615b2f64cd8103eb238eefbbe8b02520941d1c3

https://preview.redd.it/k25xy80ioi8d1.jpg?width=4032&format=pjpg&auto=webp&s=4a426ccc234737d687c7cd814322af27f0dd71a9

https://preview.redd.it/26s3u90ioi8d1.jpg?width=4032&format=pjpg&auto=webp&s=f2f48f455ea19367cd28582898f9db05ff051472

https://preview.redd.it/phoco80ioi8d1.jpg?width=2268&format=pjpg&auto=webp&s=22dc90ea4eb73bca2865242d88049cc35bfd0878