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Toshiba 50HP66 Plasma Messed up picture   Goto page 1, 2, 3  Next  
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dicepackage



Joined: 14 Sep 2009
Posts: 40
Location: Detroit

PostPosted: Sat Dec 05, 2009 7:28 pm    Post subject: Toshiba 50HP66 Plasma Messed up picture Reply with quote

50 Inch Plasma TV
Model: 50HP66
Status: Working sound, messed up picture, shuts down after one minute

My 50 inch Toshiba is having some issues. I acquired a broken TV that
was diagnosed as needing the Y-sustain and buffer boards replaced. I
did that and I went from having no picture to one with a very bad
picture.

With no input the TV has a vertical line that moves around and goes on
and off. It typically encompasses only the upper half of the TV and it
flickers on and off on the bottom half. This vertical line also appears in different places.

It doesn't seem to like having a video source on. It will stay on
indefinitely if there is no video source but if I plug in my portable
dvd player it will shut down in about a minute. It used to shut off
after only about two seconds. My question is does anyone know what
might be wrong here?

My Vs voltage should be 196 but when it is set that high it powers off if there is a video source. At around 176 it is stable with a video source. The Va voltage should be 60 but the lowest it will allow me to turn it down to is 65.

I made a youtube video to show what is wrong. Sorry for the bad
picture quality. The first video shows it with a input and the second one is with no input and then I turn it on and the TV goes off.
http://www.youtube.com/watch?v=3Xuvgoioig4
http://www.youtube.com/watch?v=IdQAdMGoapA


Last edited by dicepackage on Mon Dec 07, 2009 6:05 pm; edited 1 time in total
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dicepackage



Joined: 14 Sep 2009
Posts: 40
Location: Detroit

PostPosted: Mon Dec 07, 2009 6:03 pm    Post subject: Reply with quote

It is probably easier to see what is going on with pictures rather than with the youtube video. The first picture shows the TV after I change the volume and this comes up. The second picture shows the screen as it looks like when I am playing a video. The actual video for comparison can be seen on the portable DVD player below.


Jesse Mack



Joined: 22 May 2008
Posts: 600
Location: The Last Frontier

PostPosted: Tue Dec 08, 2009 12:08 pm    Post subject: Reply with quote

Subject: Part Numbers for Display Assembly Modules. Revised version of PDP200605.

Information Item: Please note the following part numbers for modules located on the display assembly for the 42HP16, 42HP66, 50HP16 and 50HP66 models:

Module 42HP16 42HP66 50HP16 50HP66
Control PCB 75003027 75003027 75003034 75003034

Y/T-Driver (YDRV) PCB 75003028 75003028 NA NA

Y-Driver (TDRV) PCB (Top) NA NA 75003035 75003035

Y-Driver (YDRV) PCB (Bottom) NA NA 75003038 75003038

X-Driver (XRLT) PCB 75003029 75003029 75003039 75003039

X-Driver (XRCT) PCB NA NA 75003041 75003041

X-Driver (XRRT) PCB 75003030 75003030 75003040 75003040

Y-Sustain PCB 75003031 75003031 75003042 75003042

Z-Sustain PCB 75003032 75003032 75003043 75003043

Power Sup PCB (PSU) 75003033 75003033 75003044 75003044

Please note that the VS and VA voltages have a profound impact on functionality of these modules.
If you cannot adjust the VS and VA to the voltages posted on the display panel sticker, this set will not display a proper picture.
I would suggest you have installed incorrect boards for this set.
Try looking at the original boards identification markings and comparing them to the originals identification markings.
The chart given is the correct part numbers for this set.

Hope this helps

Jesse
dicepackage



Joined: 14 Sep 2009
Posts: 40
Location: Detroit

PostPosted: Tue Dec 08, 2009 3:15 pm    Post subject: Reply with quote

I double checked and the Y-sustain board is the exact same part number as my previous board. I also got matching part numbers for the buffer boards as well.

With the Vs and Va voltages set at the exact levels the TV shuts off with any video input source connected after around five seconds. The only difference with the voltages changed seems to be the TV's color. A picture went from having a red tint to a blue tint.
Jesse Mack



Joined: 22 May 2008
Posts: 600
Location: The Last Frontier

PostPosted: Tue Dec 08, 2009 3:43 pm    Post subject: Reply with quote

Quote:
A picture went from having a red tint to a blue tint.


There should not be ANY tint. Are you talking about tint being with or without signal. Have you "twiddled" the pots on the Y-sustain?

You may also have a bad logic pcb assy with the pictures shown. Also make sure that your LVDS cable has been unplugged and replugged in as dirty contacts cause a great many problems.

Jesse
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dicepackage



Joined: 14 Sep 2009
Posts: 40
Location: Detroit

PostPosted: Tue Dec 08, 2009 5:26 pm    Post subject: Reply with quote

That tint I was talking about was probably due to the change in the Vs voltage coupled with not adjusting the y-sus board. I put the voltage back to where it should be and then adjusted the potentiometers on the y-sus board perfectly black unless you do something. I took another picture with the input and it looks just as bad. It took me several tries to get the picture since the TV kept shutting down before I could take the photo. I have reseated all the connections but the problem remains. My question is at this point should I try replacing the logic board?
Jesse Mack



Joined: 22 May 2008
Posts: 600
Location: The Last Frontier

PostPosted: Tue Dec 08, 2009 7:51 pm    Post subject: Reply with quote

Your last picture is pretty good. I have had several sets of different brands with similar pictures and some were the X-sustain and some were the logic board and even others were the Y-buffer's. Usually adjusting the pots on the Y-main is not a good idea as they are adjusted using an Oscope with proper documentation which is not available for many sets.

Good Luck

Jesse
dicepackage



Joined: 14 Sep 2009
Posts: 40
Location: Detroit

PostPosted: Tue Dec 08, 2009 10:16 pm    Post subject: Reply with quote

I know the Vs and Va voltages should be exact but when I set them this way the TV shuts off. When lowered the TV doesn't really look much different except it doesn't shut off. I have adjusted the potentiometers on the Y-main board but don't believe that has anything to do with the problem at hand. I was basically thinking the problem was the logic or Z-board. I was wondering if there was any good way of diagnosing the problem to either of these boards so I don't have to buy both parts and just do a guessing method.

By the way Jesse, you have also walked me through fixing another broken TV of mine in the past. I am really grateful for your advice so I wanted to say thank you for all your help.
Jesse Mack



Joined: 22 May 2008
Posts: 600
Location: The Last Frontier

PostPosted: Wed Dec 09, 2009 12:40 pm    Post subject: Reply with quote

Sorry, I have not found a good way to differientiate between these boards for this kind of problem although I am sure there is one.

The condition is known as over and under diffussion. The correction is usually raising or lowering the VS voltage only per the manufacturer's advice. All other voltages should be at their nominal levels. Adjusting the pots on the Y-main can cause a similar problem and even damage the buffers if carried to far. That is why I do not recommend their adjustment.

Your problem however is far worse than simple adjustments. You still have a bad board.

Note: After reviewing this complete posting I see that this is a problem.

Quote:
The Va voltage should be 60 but the lowest it will allow me to turn it down to is 65.


I have never seen any board that would not allow this voltage to go low enough other than the power supply itself.

Hope this helps.

Jesse
dicepackage



Joined: 14 Sep 2009
Posts: 40
Location: Detroit

PostPosted: Wed Dec 09, 2009 5:12 pm    Post subject: Reply with quote

I'm not sure if this makes any difference but I hooked up the tv out to another TV and that works fine.
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