STR-DG720 Problems with sound disturbances

[Tujetsch]

I bought the DG720 to replace my old sony av-receiver and to have hdmi support true all the system-components.
After setting up the system everything works but there ist an constant tone in background, whatever system ist active.
With the old receiver everything worked fine.

Advice: Only the hdmi connections are made.

Thanks for any idea

Marcello

 

[dante01]

Turn off all other components at the mains and unplug them - including the TV. Move any form of telephone that is in close proximity to the receiver. Is the noise still apparent and does it emanate from all the speakers?