General Forum

Re: Beovision 3 Buzzing noise

Spiros — Fri, 02 Jan 2009 10:24:49 GMT

Dear all,

After a thorough cleaning, so far the problem seems to be solved. Up to this moment no noise at all.

Keith thank you really so much for all the support.

Many regards to everybody.

Spiros

Re: Beovision 3 Buzzing noise

Spiros — Tue, 30 Dec 2008 04:31:43 GMT

Dear Keith,

Your support is more than a treasure!!! Many thanks.

I will follow the instructions exectly and let you know about the outcome.

Warm regards

Spiros

Re: Beovision 3 Buzzing noise

Keith Saunders — Tue, 30 Dec 2008 03:51:17 GMT

Spiros,

Whilst turning off the TV may discharge the static, any dirt is already in place, so this would not resolve your problem in my view.

In my view the service team should not need to take the TV away UNLESS the problem is NOT corona discharge because to solve a corona discharge issue all they need to do is spend 5 minutes on a cleaning job.

Re: Beovision 3 Buzzing noise

Spiros — Tue, 30 Dec 2008 03:24:09 GMT

Dear Keith,

Many thanks for the input.

It seems like a small problem.

Talking with the chief electronic eng. of my company, he saw your points and he said that if this is a case of static electricity only, I should remove the plug out of the power socket for a few hours (maybe overnight) so that any static electicity will be discharged. Do you think that such a thing could solve the problem or at least until the service picks up the TV for thorough cleaning (if the latter of course will help)?

Warm regards

Spiros

Re: Beovision 3 Buzzing noise

Keith Saunders — Tue, 30 Dec 2008 02:30:26 GMT

Spiros,

Thank you for your answers which based on them appears to put "Corona discharge" as the most likely cause of your problem.

The only way to be 100% certain is for a Technician to remove the back of the Beovision and actually observe the fault which if it is "Corona discharge" then a small blue spark will be seen with the buzzing noise anywhere along the EHT (Extra High Tension) cable from the EHT transformer to the anode cap on the tube. This is an area where the voltages are very high at around 25,000 volts, so any build up of dirt, particularly grease laiden provides a secondary route for the high voltage. If the discharge is only small it may not effect the picture.

A common time when this type of problem occurs is after a TV has been moved particular just after the set has been switched off where the remaining static on the EHT cable attracts disturbed dust.

Unless you have knowledge and experience of the repair of CRT TV's, then this is one best left to the service centre.

Re: Beovision 3 Buzzing noise

Spiros — Mon, 29 Dec 2008 16:30:53 GMT

Hello Keith,

Here are the answers!

1. The noise will come for 3-4 seconds after changing the channel but will do this very frequently now while watching the same channel without changing it.

2. There is absolutely no affect on the picture in anyway.

3. No smell of burning (Thank God!)

4. Noise is buzzing the sound like when short circuit is made (compared to this sound without meaning that there is such a problem)

Additionally, because it was mentioned for sound problems, the noise comes even when sound is muted to 00

Also, I did remove the terestrial antenna (which is connected to the modulator since the TV is used as a master and the noise did not dissapear)

Please let me know for any additional info I can give.

Many regards

Spiros

Re: Beovision 3 Buzzing noise

Keith Saunders — Mon, 29 Dec 2008 15:35:15 GMT

Spiros,

So, your problem occurs:-

On all Channels
The buzzing comes from the back of the screen and not through the speakers
It is becoming more frequent

We need to establish a little more detail, so perhaps you can answer the following questions:-

How long does the buzzing last, a few seconds each time it happens or much longer ?
When the buzzing occurs, does it affect the picture in any way, faint lines, picture breakup or any picture change ?
Is there any smell of burning ?
Is the noise really a buzzing noise or is it more of a hissing sound ?

Re: Beovision 3 Buzzing noise

Spiros — Mon, 29 Dec 2008 15:21:32 GMT

Dear Keith,

Many thanks for this detailed analysis. I indeed have the problem on almost all chanels now and even on Sat ones as well. In most of the cases the sound will come after a few minutes the TV is on and will usually will come and go when I change channels. However the noise is getting a bit worse and now in some chanels coming more frequently.

I did check thoroughly the sourse of the sound and it is not the speakers but this comes from the back of the screen.

I really appreciate your help and support on this matter which I'm sure you understand that is a bit sad since I did expect this TV which I really consider the best after my AV9000!

Warm regards

Spiros

Re: Beovision 3 Buzzing noise

Keith Saunders — Mon, 29 Dec 2008 02:31:05 GMT

With regards to this apparent buzzing noise, lets start by addressing a few points raised in this thread.

If you are getting a buzzing noise ONLY on analogue channels and from the speaker(s) then this is what is called "Vision on Sound" in the TV industry and would happen a lot on older TV's. This is where the vision carrier gets mixed with the 6Mhz (5.5 Mhz in most parts of Europe) sound carrier. In fact that is one of the key differences between PAL I (UK) and PAL B/G most other parts of Europe. The causes can be many, but the most common two are related to the aerial and earthing/power as below:-

If you have an aerial which is not correctly aligned it may give a reasonable picture, but with sound issues and if it is above a certain level then the Beovision will mute the sound and depending on the setting of the ACG (automatic gain control) may only happen for a short period.
Also if you have two aerials which are diplexed together incorrect then there will be an impedance mismatch which can also cause the same problem. If you have an impedance mismatch, then you will also find that weather conditions such as rain will effect teh condition. NOTE: Diplexed means the joining of two aerials via a diplexer to ensure consistent impedance match of normally 75 ohms.
The other condition relates mainly to earthing/power where the aerial screen is either connected to an earth or is earthed via a piece of equipment and there is a potential difference between neutral and earth of more than a few volts.

If you are getting the buzzing noise intermittently (just a couple of seconds) on any channel and the buzzing is NOT coming through the speakers but apparently from the back of the screen, then the problem is likely to be "Corona discharge" which is where there is a brief electrical discharge from the anode cable which runs from the EHT transformer to the tube anode. This can occur where there is a lot of dirt or dust build up and will normally happen when you change channels. The picture will also briefly disappear in most cases.

Given that several members have stated they have a similar problem, I think each needs to define exactly where your buzzing sound is coming from, the duration and if it happens on all channels or just analogue channels and take each persons problem as a seperate problem.

Re: Beovision 3 Buzzing noise

Spiros — Sat, 27 Dec 2008 13:21:48 GMT

Will inform you directly as soon as I have the news!

Re: Beovision 3 Buzzing noise

Craig — Sat, 27 Dec 2008 11:15:10 GMT

spirost:
Hi Craig,
Just connected a Surge protector and I have to admit there was a significant reduction. But still in some cases it is done.
I've already contacted my local B&O Techs and I'll let you know once I have it hopefully done!!!
Regards
Spiros

Thanks Spiros, if you could let me know what they find. Going to talk to my dealer again has the guarantee has now expired.

Craig

Re: Beovision 3 Buzzing noise

Spiros — Sat, 27 Dec 2008 08:45:02 GMT

Hi Craig,

Just connected a Surge protector and I have to admit there was a significant reduction. But still in some cases it is done.

I've already contacted my local B&O Techs and I'll let you know once I have it hopefully done!!!

Regards

Spiros

Re: Beovision 3 Buzzing noise

Craig — Sat, 27 Dec 2008 05:35:38 GMT

spirost:
Just another thought that came into my mind.
Could the buzzing noise might have to do with the power supply? I have the TV set on a multiplug unit along with the Beosound 4, DVD and SAT Rx. Also the buzzing noise comes only when a colorful image is appearing.
Any thoughts on this?
Craig, have you already tried a multiplug with voltage stabilizer (i'm not quite sure about the correct English word)?

Mine is connected through a Belkin Surge Protector. What I have noticed is with my noise it is more to do with sound than picture brightness. Going to have a play with the brightness settings just to check though.

Craig

Re: Beovision 3 Buzzing noise

Spiros — Fri, 26 Dec 2008 23:45:45 GMT

I think it should be what Robest mentioned. Is it possible that this can be fixed in the house and not take the TV to the B&O techs?

Re: Beovision 3 Buzzing noise

Peter — Fri, 26 Dec 2008 16:11:51 GMT

Sounds like multimedia Robert has the answer to that one. May be something a little loose from transit.