High pitch whine when bed heater is on?

Recently my SM2 350 has started making a high-pitch whine. At first I figured it was likely one of the linear modules, but it turns out to happen whenever the bed temperature on the display drops below set point (and the heater turns on). It is super load and annoying.

I’ve verified that the build plate screws are all securely fastened and nothing is loose on any of the linear modules.

It is very difficult for me to pinpoint where the sound is coming from, but I’m guessing it might be the power supply.

Has anyone else experienced this or have any ideas how to try to rectify it?

When I’m trying to find the source of a sound, I find touching things to help. Particularly if you can touch a part, then start the noise, then stop the noise. Although if the pitch is high enough, you might not be able to feel it. I’ve seen posts about pretty much every part going bad, so you will want to narrow it down to a single part.

If it is the power supply, it could be a couple of things. There have been several posts about various noises and repairs people have made to the power supply.