Buzz coming from Marantz sr640 receiver

[jefferj16]

I have a Marantz sr640 receiver. A buzz is coming from the receiver at mid volume level. I isolated the problem and my problem is not a ground loop problem. After disconnecting everything accept the speakers, turning off and back on the receiver, the buzz was still there which indicates that the problem is in the receiver. What should I troubleshoot inside of the receiver?

[HayZee518]

replace the filter capacitors in the power supply. one or more are leaking.

[Larry at Approved]

Does the hum get louder and softer as you turn the volume control up and down? Does it go away when the volume control is set to minimum?