Need to replace the transformer in my home theater amp.

Hallo.

New to this.

I got a surround sound system from a friend but seems like I need to replace the transformer in it. I am struggling to find a replacement. Your help would be greatly appreciated.

Reason for me thinking I need to replace it is because it’s humming on all speakers. The humming alternates, louder then softer, less then more aggressive. Leads me to believe is mechanical humming, not ground or signal. Starts humming as soon as I switch the power on, even when inputs are removed. Humming does not change with volume adjustment.

I don’t know much so your help will really be appreciated.

Attached a picture of the transformer.

Unit is a BNW MK-33.

Thanks again!