50H81(toshiba) Horizontal Lines


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50H81(toshiba) Horizontal Lines

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DoubleBar-S-
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Mar 16, 2005, 6:25 PM

Post #1 of 7 (1937 views)
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50H81(toshiba) Horizontal Lines	Can't Post

Hello all,

I have a Toshiba 50H81 with problems. It has intermittent horizontal lines associated with a loose connection that I can't find. The lines are hard to describe, but there are about 50 of them ranging from 1/4" to 1" in size. When these lines are there, you can't make out any of the picture. The color of the lines change with the video being fed to it, but that is all you can make out of it.

I have narrowed it down to the digital convergence board, but I can't seem to fix it. I have had this set taken apart about 10 times, and every time I re-solder the entire digital convergence board, and the connector for the main board(I believe 24 pin connector), but I can't seem to fix it. When these lines show up, I can either tap or wiggle the convergence board, and it will clear up. It may last for 10 seconds or 10 hours before it does it again.

Any help would be appreciated. Or if you can tell me how I can get a new digital convergence board, I could try to replace it.

Thanks,

DoubleBar-S-

minehunter
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Mar 17, 2005, 9:31 PM

Post #2 of 7 (1927 views)
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Re: [DoubleBar-S-] 50H81(toshiba) Horizontal Lines [In reply to]	Can't Post

On this model I beleive there is a small standup board in the middle of the main board. It is connected with a white plastic double row plug. I have found that there are some connections on this boards plug that crack. when they crack, they will cause Lines and also portions of the picture to just go away. I hope this helps you out.

DoubleBar-S-
New User

Mar 17, 2005, 10:27 PM

Post #3 of 7 (1926 views)
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Re: [minehunter] 50H81(toshiba) Horizontal Lines [In reply to]	Can't Post

Yeah, that's the board. It is the digital convergence board, and I can't find any cracks. I was thinking about hard wiring that board to the main board to try an eliminate that connector, but I know if I get just one wire crossed, it is liable to fry....

Are you referring to the metal pins of the 24 pin connector cracking, or the convergence board/main board's solder points cracking? I have desoldered the connector from both the main board and the convergence board, and cleaned up the solder pads with a fiber glass pen, and haven't been able to find any cracks on either side, but I could have missed one. I might just trace from each solder pad to the first component and solder jumpers for every pin. I might just go the hard wiring route.

Thanks,

DoubleBar-S

jarasan
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Mar 18, 2005, 3:57 AM

Post #4 of 7 (1922 views)
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Re: [DoubleBar-S-] 50H81(toshiba) Horizontal Lines [In reply to]	Can't Post

Have you tried tried thermal testing (cooling, heating) the affected board, if you hardwire it and the problem remains its a pita to backtrack, use very bright light and a magnifying glass to inspect the suspect PCB.
Jarasan

DoubleBar-S-
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Mar 18, 2005, 5:41 AM

Post #5 of 7 (1919 views)
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Re: [jarasan] 50H81(toshiba) Horizontal Lines [In reply to]	Can't Post

I haven't tried thermal testing yet. I didn't think it was a thermal issue, since it will do this at either time... when the set is first turned on, or when it has been on for 12 hours. I think I will get a good magnifying glass to check for cracks though. I hope there is one I just haven't seen yet.

I do notice one thing though. After I take it apart to try to fix it, it can take up to a week to start messing up again. I don't know if this has any relevance, but it is odd. After I try to fix it, I can tap, wiggle, hit and do all sorts of things to that board, and can't get it to show any signs of messing up. But, after several days, it will start to do it again. Maybe it is a thermal issue.

One repair tech has already given up on it (back when it was under warranty), and I used to be a repair tech, and I'm about to give up on it too. I just want to shoot it, but it would cost me too much money to replace it.

Thanks for all the help.

DoubleBar-S

minehunter
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Mar 18, 2005, 9:27 PM

Post #6 of 7 (1911 views)
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Re: [DoubleBar-S-] 50H81(toshiba) Horizontal Lines [In reply to]	Can't Post

The toshiba repair that the factory techs recommended was to just replace both side of the connector.

DoubleBar-S-
New User

Mar 19, 2005, 3:18 AM

Post #7 of 7 (1907 views)
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Re: [minehunter] 50H81(toshiba) Horizontal Lines [In reply to]	Can't Post

I guess I'll have to hunt around and try to find a new replacement connector. Just curious, is this a common problem with this set?

Thanks for all the help.

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