Infinity blue pulsing lite

Hello everyone, the situation is as follows.
I bought a PS4 pro as a non-working one, or for spare parts to try to repair it. At the very beginning, it turned on for 3 seconds, there was a blue flash and it turned off.
Later, I put 3 washers under the APU/CPU mount, and after that it stopped shutting down. But the blue light doesn’t go away, it just stays on endlessly and doesn’t turn to white until I turn off the console itself.
I can’t switch to safe mode, because when I hold down the power button, it turns off after a while, but does not switch to safe mode. And the problem is definitely not in the power supply, because the console works, and not in the hard disk, because I checked it on a PC and it works.
Also, please tell me if the light should turn to white if the console is not connected to a monitor, and if the hard disk needs to be reconfigured somehow if it was once used on a laptop.