Help: Noisy Rowland 10 power supply

I did not use my Rowland 10 for several weeks; I left it plugged into the AC outlet, but not on.
When I turned it on today, there was a continuous loud buzzing sound from the power supply that didn't go away. Surprisingly, it could still produce music through my speakers. Any idea what's going on?

I've decided not to use it for now because I'm afraid I may damage it even more, and worse, I may also damage my speakers.

I will call Rowland on Monday ... but I just wanted some feedback this weekend, to release some tensions :(

Thanks.