Crying 12V PWM Powersupply

[M249]

Helo there, my name is David, 25 years old an i come from germany near Dresden.
i have a Hifonics Colossus XI Amp, with a little bit more cap-buffer on the secondary outside from the Powersupply (better capaciators, same voltage, but more µF). Over a year works great, but now the powersupply is crying under load. When i power on the Amp an load up the Capacitors it will cry, and when i hear musik with bass the powersupply make some noise that scary me :/ .
The Amp works great, but that noise .


i have make a video to hear it:
YouTube - Colossus XI schwingendes Netzteil

What is it? only the two coils that winding is loose? what can i do?

thanks for answers, and a merry chrismas all