High frequency noise on the output of my HiFi :(

[iCore]

Hello everyone

So here's the problem,
On the ouput of my Hifi audio system, i hear a High frequency noise
I've tried to use an oscilloscope but it turns out the only noise I see is around 25kHz, which surprises me because i didn't thought i could be able to here above 20kHz .

Whenever i change the audio input (Line, DLNA, Airplay or USB) I still get the noise.
The case is made of metal and when I mesured with my multimeter, i got some voltage but even when i grounded the case, the noise was still there. :/
Also when i turn the volume all the way down to mute it, the noise disappear

The model is the following : Sharp XL-HF401PH
I've bought it around 2 years ago and the noise appeard few months ago but it's only now that i am trying to repair it

Any ideas ?

I'll try to make some inside pictures tomorrow

[T3sl4co1l]

Could be a number of possibilities... including simply bad design, if it's anything consumerist.

Aging would seem to suggest electrolytic capacitors, perhaps an unstable switching supply as a result.  Can you take some pictures of the PC boards inside?

Tim

P.S. Max avatar?  Now there's a classic

[Paul Moir]

It could also be something external interfering with it.  As a first step try unplugging everything else around it (in the house) or better yet taking it somewhere else.