ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
I bought a Beomaster 4400 last week and whilst pleased with its performance a slight amount of mains hum at switch on, which initially went as the unit warmed up, has now turned into something quite horrendous and I can no longer use the receiver. The hum is present regardless of volume setting and input selection so I'm suspecting the unregulated power amp power supply has fail in some way. Does this should sensible?
I ought to replace the two smoothing capacitor anyway given the units age (OC8 &9), is there any preference in part type?
Thank you for any help given.
Karl
Is it from the Beomaster or through the speakers? The transformers can delaminate and hum badly - certainly do on the 3000 - short term fix is putting two halved squash balls under it and this reduces the noise!
Peter
Good point Peter!
Also try the LINEAR mode to see of the hum comes from the tone control or from the preamp or the output stage...
Check the idle currents.An overloaded power supply can easily cause hum.
Martin