I have a brand new Beovision 8-40 and my screen seems flawed. Occasionally I get some lines of alternating black and white pixels at the top-most part of the screen on the left side. As I most times use the cable box for content, I see it then only.  I will try the other sources and look for it.
Something is not right and I do not think it is the signal.
Any ideas?

Congodog

How big is it? Is it only in the corner?

congodog:

As I most times use the cable box for content, I see it then only.

what is the connection / cables from the STB to the BV8 ?

does it regularly happen on some times of broadcasts / channels ?

elephant:

does it regularly happen on some times of broadcasts / channels ?

If the "pixels" are rather wide (less than 100 on the entire screen width), it could be the vertical interval time code (VITC) of the original broadcast source tape bleeding through. It's a binary code that is used to identify each picture frame among other things.

These sometimes show when they have been recorded on more TV lines than usual and the broadcaster's program chain hasn't been configured to suppress them. You didn't see them much in the CRT days, since the sets had a lot more overscan because the tube edges weren't straight, but flat panels are often adjusted more aggressively to show microphones, studio light barn doors, edges of stage props, time codes etc that used to fall in the overscan area

I'll try to find an example image so you can judge whether it might be this or something else.

As others have said, it does sound a lot like the 'cue dot' that is often used by broadcasters during live broadcast to inform their regions when the adverts are about to begin.

Does it happen just before or at the end of an ad break, and does it look a bit like this?

I see these from time to time on my BV8-40...  I assumed it was a problem with the source signal... It does look similar to the above graphic.

Stan

Took a while but I managed to find an example of what I was talking about. Another source for these might the WSS info (wide screen signalling) which delivers the intended display aspect ratio of the source material. That is a static bit pattern (except obviously when the aspect ratio changes) while the VITC moves all the time. This example pic includes both.

Often you see these only on the left half of the topmost picture line, then they are usually remains of an improperly made letterboxing of the source material.

Neither case is a problem with your TV.

a most appropriate sub-title in the picture

yes, I occasionally get this and the other type mentioned above

I have always believed they were temporary problems introduce by the broadcaster