Whenever I have to fault find mains problems, then I hire a Dranetz. You can see details of them HERE

They can be hired from several places including HERE I would expect B&O to have one of these as there are a lot of power and earthing issues today.

What is the problem with your Beovision 7-40 ?

Richard,

I would be very surprised if there is anything wrong with the Beovision 7, this is much more likely to be caused by earth imbalance directly linked to mains load.

What kind of property do you live in ? in other words, is it a flat where the mains coming into the building could be shared or are you in a detached house with its own supply?

You say "After about a week" do you mean you have only had the Beovision 7 a short time ? and the problem appeared a week after you took delivery ?

Have you unplugged the Masterlink plug from the Beovision 7 to see if the problem still exists ? if not I suggest you do that.

Is your Beovision 7 connected to a Cable, Freeview or Sky STB and if it is connected to a Cable STB, has the incoming coax line been connected through a Galvanic isolator ? If you do not know what a Galvanic Isolator is, then click HERE and it is shown about half way doen this FAQ,

Are you a technical person who could take some measurements with a multimeter ?  

Richard,

You have made an important statement in your last post which throws a whole different light onto the situation. You said:-

"Forgot to add when the 7 shuts itself off you don't get the curtains , it's a hard shut down , screen goes black and no stand-by light for 10 seconds"

So, it shuts itself down as if there were a power fail, this in my view is a key point.

Richard,

After giving this further thought based on your last key statement, I think you either have:-

• A problem in the "Power Factor Correction" circuit in the Beovision power supply OR;
• There is a phase lead or lag on your mains power causing a potential difference between neutral and earth.

If you have a multimeter set it to the AC range 200 volts. Connect one lead to the neutral (left pin) of the mains plug and the other meter lead to the earth pin. The voltage should be zero at best and no more than a few volts at worst. If it is a large voltage (greater than 20 volts), then we are onto the problem. If you do not have an auto range multimeter you may need to lower the range step by step manually.

Richard,

Its not really the voltage drop which is going to cause the problem and it would have to be a big drop to stop the Beovision working, but if it were big enough it is likely it would effect other products as well.

Let me explain. All power generated and distributed in the UK starts off as "Three Phase" you must have seen the signs on the power lines saying 415 volts, well that is a phase to phase voltage. The Electricity company need to try and keep these phases balanced and if one phase draws more current than one of the other phases, then the virtual "Neutral" will have a potential difference with earth which we do not want. In modern homes built in the last say 20 years earth and neutral are bonded at your meter meaning unless you have a wiring fault in your home the voltage between earth and neutral will be around zero.

However in older properties this was not the case and hence why I am suggesting measuring between Neutral and earth.

a2bur:

 I also got an oscilloscope , haven't got a clue how to use it , the wife doesn't know that and thinks I very clever  .

Richard

Andy T.

Richard,

Well, with only 1 volt between neutral and earth, that's good. It is also good that your cottage (well some cottage with 22 rooms) has been rewired.

Has the Beovision 7 failed since you removed the Masterlink cable ?