u/AnyBelt9237

At my day job I repair a lot of Sonos speakers and 2 specific models (Playbar and amp) often produce high pitch sound from the trafo and replacing caps or the trafo it self has no effect. Any other suggestions? For the amp I have replace a lot of components near the trafo and in the startup circuit but nothing made a difference. Amp usually blows up some resistors, chips, brown smd caps and a inductor. After repair, it almost always has high pitch whine or buzzing sounds.