Onkyo TX-NR555 buzzing noise

[Caplaur]

Hi everybody,

My Onkyo tx-nr555 receiver (bought 2 months ago) is making a loud buzzing noise when it's started.
The buzzing decreases and eventually disappears after 40-50 mins. If I shut down the receiver and power on again the buzzing starts again. The noise is coming only from the receiver not from the speakers (5.1 system). Even if I disconnect all devices (TV, BluRay, Streambox, speakers) the noise is still there.
Every time it's the same pattern, he buzzing decreases gradually but it takes about 40 to 50 minutes to stop.

Any ideas what this could be ?

Thank you very much.

 

[lovinthehd]

Perhaps a transformer mounting issue?

 

[TLS Guy]

Hi everybody,

My Onkyo tx-nr555 receiver (bought 2 months ago) is making a loud buzzing noise when it's started.
The buzzing decreases and eventually disappears after 40-50 mins. If I shut down the receiver and power on again the buzzing starts again. The noise is coming only from the receiver not from the speakers (5.1 system). Even if I disconnect all devices (TV, BluRay, Streambox, speakers) the noise is still there.
Every time it's the same pattern, he buzzing decreases gradually but it takes about 40 to 50 minutes to stop.

Any ideas what this could be ?

Thank you very much.

You have an improperly potted power transformer. The core can vibrate at 60 Hz mains frequency.
As the transformer windings and core heat up expansion takes place and tightens things up and the buzz stops.

This is a faulty power transformer and your receiver needs replacement under warranty.

 

[lovinthehd]

Contact Onkyo warranty service would be my next step unless the retailer wants to run interference for you....

 

[Caplaur]

Thank you very much for all replies, I have contacted Onkyo and they sent me to a service center.

 

[Caplaur]

You have an improperly potted power transformer. The core can vibrate at 60 Hz mains frequency.
As the transformer windings and core heat up expansion takes place and tightens things up and the buzz stops.

This is a faulty power transformer and your receiver needs replacement under warranty.

You were right, I'm back from service center, they replaced the transformer.

Thanks again

 

[TLS Guy]

You were right, I'm back from service center, they replaced the transformer.

Thanks again

Thanks for the feedback.

We do have to play "Stump the Chump" here frequently.