HTS6515 - constant noise/ruis

Hi,

After not using the system for a couple of months I switched on my HTS6515.

Result: a constant noise (ruis) regardless of the system volume or input.

Inputs tested: DVD, Radio, Aux, MP3, HDMI, SCART
--> same result
(no noise with the "DIGITAL INPUT" source, but I don't have digital input devices)
Volume: low (1 or 2) up to 15
--> same result
Tested: Without 2 external speakers (the '2.1' speakers)
--> same result
Tested: With nothing connected (only radio antenna)
--> same result

Other things tested: different power plugs, different house, several input sources like iPhones, radio's, MP3 players, etc.
Playing MP3 on USB stick has the same result: Music + noise (noise volume level remains the same, even if you turn up/down the volume)

Being desperate now I turn my cry for help to the community :)

Any idea what could cause this constant noise (ruis) ?
Maybe a (small electrical) component that could be replaced? (I'm quite technical)

DJ

Update: I am running the latest firmware V24.02.41
a 're-upgrade' did not solve anything

NOTE: the noise (ruis) comes from the 2 external speakers.. No noise from the base speaker.
Connecting 1 or 2 external speakers doesn't make a difference

Try to reset to factory settings and if nothing changes then it has to be checked :(