What to replace to eliminate the squeak of a switching power supply?

Question

Batteries

Good afternoon.
Bought 4 pcs. here are such funny, Chinese power supplies:

2 pcs. - 220V to 5V
2pcs. - 220V to 12V
5V work well, no issues with them. But 12 volts squeak when turned on (without load).
I could not find schematic diagrams for this miracle. There is a suspicion that this is a 400V 4.7mf capacitor beeping.
Tell me, please, is it possible to overcome this annoying squeak and how? Thank you!

Answer 1

• Electrolytic capacitors by themselves cannot beep. In extreme cases, they can provoke a squeak.
  
• Squeaks - the core of the inductor-transformer (PS see Magnetostriction). Why not forget about it, because without a load it will not work?
  
• If you want to figure it out, you will have to copy the circuit from the board.
  

Answer 2

Most likely throttle squeaking.
https://www.youtube.com/watch?v=SOjlY_wlsZ8
https://www.3dtoday.ru/blogs/goolya/eliminate-squeak-bp

Answer 3

I would test conderia, yesterday I changed 4 pcs in a power supply unit on a PC, because of a terrible squeak in idle time!