TV Interlace

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BernieD

BernieD

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Joined
Mar 1, 2005
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5,891
Location
Goodyear, AZ
A strange (to me) problem has developed in our front TV (24" JVC flat tube TV circa 2001). The problem seems to be in the TV, not connections or inputs, since I am getting the same problem regardless of input.

I have about a dozen or more thin white lines running across the top of the TV screen. Then just below the white lines is a string of white dashes across the screen. The picture is not cut off showing the full picture to the top, tho at times an inverted image is reflected in the white line area. When the problem first began, it cleared up after the TV warmed up for 10-15 minutes. Now it is always on.

The RV has been used for almost 8 years now, so I am not sure if this is an initial sign of death by a thousand lines, an adjustment needed or just something we should live with until the TV gives up the ghost.

Anyone have any thoughts?
 
We had a problem with our house TV a bunch of years ago with the white lines at the top .... think we also had lines at the bottom, too. Bottom line was that the TV was toast, sold it for $10 at a yard sale. Maybe it's time for an upgrade?? Jus think of the fun Terry and Mike and Jeff could have swapping out your TV at the FMCA rally !!

Wendy
 
Bernie, It's a vertical sync problem.  Most likely a capacitor went bad.  The component(s) themselves would be cheap, but the labor might be prohibitive.   

If you want to get a "ball park" estimate, tell any potential repair man that you have a set with "Vertical Overdrive" (technical description of the inverted image) and visible retrace lines at the top of the screen.

Best fix.... That new LCD/HD model that you've been wanting anyway.

BTW - This condition you are observing usually doesn't last very long as the transistor responsible for vertical sync is running very hot and won't last forever.

Good luck....
 
I assume this is a CRT type television.  The NTSC television standard includes some lines that are called Vertical "Sync" in the very old days these showed up as a horzontial band of black if your Vertical Hold was off.

Now days these portion of the signal contains a bunch of information, For example Closed Captioning is in there, There is information on where the show originated, and other digital info that some televisions and/or Video Recorders can process.

What has happened is one of two thigns.

Either the station has "Squashed" the picture a bit (this is common when the show is sent to the station in HD format and they are re-broadcasting in Pan& Scan.. They may depress a bit which actually makes it look a bit better)

The other option is the television is very slightly out of adjustment (Vertical Size)

WARNING: Adjusting the size controls on a black and white set.. Chlid's play (Which is to say I've been able to make that adjustment since I myself was a child)

On a color set it requires special test tools and is best done by a trained technician.  (Which is why they no longer put the knob where you can get at it)

The reason for this is if you change the size setting it can mess up the color big time, red can become blue or green (Mix 'em up any way you like)
 
I'm in agreement with Tom; Your TV is messed up.

Upon my original read my first thought was Horz blanking pulse, etc. Then reading John's post I was further convinced and in agreement with John.  But then it occurred to me, it isn't supposed to be doing that, the problem is in the TV. 

A good tech, familiar with that specific set and that problem could likely diagnose and fix it in less than an hour, and most shops charge a min of one hour anyhow.  However I don't know if such shops exist anymore, other than the mfg.  We have become a disposable society!  Best Buy, WalMart, etc. would likely be the cheapest solution.
 
John From Detroit said:
I assume this is a CRT type television.
Click to expand...

John, if you read the post, it says that the TV is a tube TV. Aren't all tube TVs CRTs?

Either the station has "Squashed" the picture a bit (this is common when the show is sent to the station in HD format and they are re-broadcasting in Pan& Scan.. They may depress a bit which actually makes it look a bit better)
Click to expand...

John, if you read the post it says that the problem occurs using other inputs as well as TV.
 
Thanks to all who have responded. It sounds like the best way to unmess it is to replace it. Talked to my extended warranty company this morning and they will cover the replacement. Now I can go to Costco and get a larger LCD model and, yes Marsha (" Jus think of the fun Terry and Mike and Jeff could have swapping out  your TV at the FMCA rally !!)", we can have fun at ABQ. :D
 
This thread reminds me of a cooking show script on the FOOD channel.
 
  Original Post:  Bernie says his "TV souffle  doubled over at the top". :(
 
  My Post:  "one of the capacitors  ingredients may be bad"  :-\
 
  Tom's Post:  "The whole dish tastes like crap is messed up" 8)
 
  JFD's Post:  "I know three different recipes for that dish.  One is  good, one is not and one may be for something else entirely, yada, yada,  yada" ::)
 
  George's Post:  "I agree with Tom and JFD..." ...but they said different  things..DUH? ???
 
  Wendy's Post:  "Whatever... let's party down in ABQ" ;D
 
  Bernie's Post:  "Marsha, ..errr Wendy, I'll bring  the booze TV... see  ya in ABQ" ;) :D
 
  I feel like a cook among Chefs.......
 
 
 
Lou:

Too many cooks in the kitchen or too many fingers in the pie?
 
BernieD said:
John, if you read the post, it says that the TV is a tube TV. Aren't all tube TVs CRTs?

John, if you read the post it says that the problem occurs using other inputs as well as TV.
Click to expand...

I must have missed that line in his post.. Well. the CRT is a tube, but .. "Tube Type" means something else in Television lingo.. Kind of complex and not worth worrying about

If he stated it was a CRT type television, then I guess my assumption was a safe one wasn't it?

For those who mentioned the horzontial blanking pulse.. Tha's a series of white lines.  It is the "Vertical Intervial Retrace" pulse that he appears to be seeing.


I can't believe I actually STUDIED all this stuff in College
 
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