Hi frequency noise in center channel

[timmay8612]

Hi all, been a while since I've posted here. Having a problem I'm not sure what to make of. My receiver is periodically making a really high frequency whining kind of sound, I believe only in the center channel while watching movies. Its not for very long, only a minute or so. Then it will stop.

The noise is so high my wife can't hear it. Any ideas what could be the problem? Is the amp going out?

 

[TLS Guy]

Hi all, been a while since I've posted here. Having a problem I'm not sure what to make of. My receiver is periodically making a really high frequency whining kind of sound, I believe only in the center channel while watching movies. Its not for very long, only a minute or so. Then it will stop.

The noise is so high my wife can't hear it. Any ideas what could be the problem? Is the amp going out?

Are you sure it is not coming out of your TV?

This is a common problem for TVs but would be very unusual for a receiver.

 

[timmay8612]

Mm. Good thought. I have heard of TV's doing this, especially when there is heavy amount of white or light colored content being displayed, but so far I haven't noticed any. I'm using a Panny plasma FWIW.

I suppose the next step would be putting a different speaker in place of the center channel to rule out the speaker, although it seems unlikely that the speaker would do it so intermittently.

 

[TLS Guy]

Mm. Good thought. I have heard of TV's doing this, especially when there is heavy amount of white or light colored content being displayed, but so far I haven't noticed any. I'm using a Panny plasma FWIW.

I suppose the next step would be putting a different speaker in place of the center channel to rule out the speaker, although it seems unlikely that the speaker would do it so intermittently.

A passive non powered speaker can not generate a high frequency oscillation, so changing the speaker is a waste of time and effort.

This will be TV time base noise almost certainly. Panasonics are known to develop this problem.

There is a remote possibility it is your receiver.

 

[timmay8612]

A passive non powered speaker can not generate a high frequency oscillation, so changing the speaker is a waste of time and effort.

This will be TV time base noise almost certainly. Panasonics are known to develop this problem.

There is a remote possibility it is your receiver.

When you say time based, what exactly do you mean? Any ideas why I'm not noticing a pattern yet?

 

[TLS Guy]

When you say time based, what exactly do you mean? Any ideas why I'm not noticing a pattern yet?

It's the oscillator that drives the scanning. I have no idea what makes it intermittent, but we have had previous posts from Panny owners about this. This is a problem with all TVs to a varying extent. Put up with it. It is not worth worrying about. As you age you won't hear it anyway.

 

[timmay8612]

Any reason that you can think of that it would all of the sudden start?

 

[TLS Guy]

Any reason that you can think of that it would all of the sudden start?

No. Everything starts some at some point. A TV like that has thousands of components. So any one can drift or begin to fail at anytime.

Since it is intermittent, you will never find it in a service department. If you consider service then you will have to wait to the point that it does it pretty much all the time.

 

[timmay8612]

Ok, well thanks a ton for the information. I wonder why this isn't more publicized if its such a common problem with Panasonic TV's?