VBI signal on 50 inch Panasonic plasma TV?

[tedescm]

I recently purchased a Panasonic Plasma HDTV. Every once in awhile, I see a very small thin light at very top of the screen running horizontally and it usually flickers.

I called Panasonic and they said it was the closed caption line that comes in on line 6 and it part of the broadcast signal.

Does someone know anything about this issue?

Do all HDTV’s have this?

[Ratman]

All TV's receive the signal. It's called the VBI (vertical blanking interval). This contains CC as well other necessary signal info. When the overscan of the TV is set properly, this should not be visible on ANY TV.

http://en.wikipedia.org/wiki/VBI

EDIT: I modified the title of the thread.

[57U]

The VBI usually only shows on the upconverted 4:3 programming on HD channels and is the broadcaster's fault. If it bothers you, watch the equivalent SD channel. If it shows on true HD programming, then your overscan is set below 2%.

You can check the overscan on your TV using one of the setup DVDs discussed in the HDTV FAQ "What you need to do to your new HDTV".

Some plasmas allow overscan adjustments. Some do not.

[tedescm]

The Panasonic service center said there is nothing that can be done with this problem. Can a repair man fix the overscan or should i return the set to Costco and get another brand of TV?

Do othe brands of tv's have this problem....that you know of

thanks,

M

[57U]

Does the VBI appear on true HD (16:9) or regular SD (4:3)?

If it does then there may be something wrong with the overscan.

I have seen this on a number of Panasonic Plasmas that I've calibrated. I usually check the overscan and it's often dead on 2% on all four edges. At that, you should NOT see VBI on true HD, but you CAN see it on some upconverted 4:3 material as I mentioned earlier.

Do you have a setup DVD? Have you properly set up your TV as indicated in the FAQ I referenced?

[tedescm]

The VBI line appears on HD (not sure if it's true HD).

I've also seen it on SD. I usually do not view 4:3. I usually use the "just" mode

I do not have a setup dvd but i'm going to talk to a freind who has one and hopefully knows how to use it.

Is this common with HDTV?

tx for the help.

Mike

[57U]

True HD is 16:9. 4:3 signals on an HD channel are upconverted (with black bars) and that's what I was referring to as being a source of the problem.

If you use "just" on the SD channels, then it won't be an issue there since the just increases the amount of overscan.

So, the only thing left is if you see them on true HD (16:9). If you don't, then everything's normal.

PS, I suggest you learn what true HD is. See the HDTV FAQ "What's on in HD". The 4:3 programming on HD channels is not HD.

[tedescm]

Thank you for all your help!

[tedescm]

To 57U:

You were right on…

During the weekend I had the opportunity to view my new Panasonic 50 inch plasma. The VBI line is only visible (sometimes) on HD channels that are NOT broadcasting true HDTV (16x9). I think you referred to it as 4x3. Even then, it's just once in a while.
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For example, last night I watched the Dallas game, which was broadcast in HD, but the commercials were not in true HD and the VBI line never appeared. It seems to be a very sporadic thing.

The VBI line on my tv never shows on non- HD channels.

I asked a neighbor, who owns a HDTV and uses the same cable service as me about this situation. He informed me that he also sees the vbi line once in a while. He did not know what it was and assumed it was a bad signal. I guess this is concidered "normal". HDTV has a lot of issues...

What causes this line to sporadically appear?

Thanks for all your help…. you seem to know more about TV's than the tech service people at Panasonic.

That's a compliment!

Mike