PS4 Slim beeps once then turns off

Hello Guys,

i have two PS4s here with the same error: Pressing power button turns the PS4 on, i hear a beep and the blue light goes on, after 1 second it goes off again. So one PS4 is a classic/fat one which I was able to fix by applying more pressure on the APU, so classic fix by adding washers to the APU clamp. The other PS4 is a slim model and applying pressure to the APU didn’t help.
Now my question is can the error be the same on the PS4 slim like on the Fat model or is it something else on the PS4 slim with this simptoms?
I had the Power supply in mind since it has some heavy coil whining but 5V is on and when the power and blue light is on for a second the 12V rail is working. Could it still be the power supply? how to check, or any other tips on this error?
The board has no obvious damages like liquid or burns and no parts getting hot.

OK i tested the PS4 with another power supply, same fault. Blue light, short beep and then nothing. Any suggestions? I guess its the APU so nothing to fix?