K2000RS - Buzzing Power Supply

Hi, My Kurzweil K2000RS is working well but I have noticed a buzzing sound internally which appears to be coming from the power supply. The PSU is a Dong Ho K2000R DH0098C but I have not been able to find a new replacement - it’s probably been out of production for a long time. Is there an equivalent power supply can be swapped in or anything that can be done to the existing unit to stop the buzz? None of this is coming out of the analogue outputs - just ambiently.

It’s probably the transformer, since it works by electro-magnetism. They do hum sometimes. If it bothered me I’d look into how it mounts to the case and fitting some rubber washers or something under the mounts to stop the noise (ensuring it remained earthed though).