Fuzzy noise from the PCB (home theater)

[Vinodsalim]

I noticed that my home theater makes a fuzzy noise(noise that comes from a tv when the antenna isn't connected) from its inside, so i removed the cover and observed, the noise comes from the area where in the picture i posted, i have no clue of what component makes that noise to replaceitr, the capacitors or the ICs beneath the heat sinks...please help...

https://ibb.co/mBNBs0 image link

 

[kellys_eye]

Pictures don't show.

Some modern SMPS (switched mode power supplies) make a high pitched 'hissing' noise when under different states of load (or non load). It's not usually noticeable and certainly shouldn't be loud enough to be heard with the covers on! or from (say) a foot or so away from the equipment.

Unless there is a specific fault then the golden rule would be 'if it ain't broken, don't fix it'.

 

[Vinodsalim]

Pictures don't show.

Some modern SMPS (switched mode power supplies) make a high pitched 'hissing' noise when under different states of load (or non load). It's not usually noticeable and certainly shouldn't be loud enough to be heard with the covers on! or from (say) a foot or so away from the equipment.

Unless there is a specific fault then the golden rule would be 'if it ain't broken, don't fix it'.

I think the power supply unit is fine as i replaced some blown caps and resistors of it a while ago, this loud noise comes from the main board if the unit, especially when i switch the mode to Aux, fm etc... But when the mode is in DVD, it does not make a noise....

And this noise increases when i increase the volume....FYI, this loud fuzzy noise will be still there even though when the speakers aren't connected

Image if the area where the sound comes
https://ibb.co/mBNBs0

 

[kellys_eye]

SMPS's operate by varying the duration of a pulse according to the output load and to maintain a steady voltage.

The 'noise' you are hearing is changing as the load does - increasing the volume increases the load, switching different systems in/out also changes the load. Once the load gets to a certain level the frequency of operation of the SMPS might go outside your hearing range or outside the point at which resonance in the inductor becomes audible.

If the system is working then what is the problem?

I repeat - if it ain't broken, don't fix it.