High-pitched noise coming from T19P E2

[pmarks]

I've been running a T19P E2 for 4.5 years, powered from a PoE switch. Last month it started making an awful high-pitched noise continuously.

I looked inside, and the noise is coming from a coil on a small circuit board. I considered covering it with hot glue or something, but the parts are too densely arranged and it's not even obvious how to desolder it.

I was able to work around the problem with a USB to 5.5mm x 2.1mm barrel cable. Whenever I connect it to 5V power, the coil whine stops. This seems better than throwing the phone in the trash, but I preferred to run it from a single cable.

I wonder if there's some way to obtain a replacement PoE board?