Why does my computer monitor turn off?

Question

Iron

Good afternoon.
The monitor at the desktop computer began to go out. Moreover, each time it works for a different time: it can stand for 2 days, or it can turn off after 40 minutes. What could be the problem? What to pay attention to first of all?
Everything is in order with the system blocks: everything is spinning, the LEDs are blinking. There are no complaints about the wires either. Bios is configured normally, time is not brought down at least. Everything was fine before.

Answer 1

99% that the capacitors in the monitor power supply are swollen