Hello everyone!
The problem is as follows: when the PS4 is turned on, it emits one beep, then immediately turns off (sometimes after a second, sometimes after a couple of seconds). I checked the power supply - it is fine, it gives out a stable 5V and 12V, tried another power supply - the situation is the same. Also I tried another motherboard - the situation is the same. I tried all the manipulations with the power cable, all kinds of combinations of other cables, holdind power button (i cant enter safe mode) and so on. I even tried a different blu-ray and hard drives. I also tried changing thermal grease, thermal pads, blowing dust.
Actually, I don't understand what to do next. Of the components that I have not changed yet - the fan, the Wi-Fi antenna and the case (???) remain, can the problem be in any of the above?
Thanks a lot for future help!